Leona Build Guide by AmrasTaralom
Not Updated For Current Season
This guide has not yet been updated for the current season. Please keep this in mind while reading. You can see the most recently updated guides on the browse guides page.
Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Threats to Leona with this build
I'm writing this guide because... free Leona week is now over and as always in free Leona week I saw many, many players struggeling with her (this may also be due to the recommended items for her which are just... bad). The reaction of those players after a lost game is then most often: "She's not viable". That's so wrong, Leona is one of the most underrated and underrepresented champions of the League.
Moreover, some players playing Leona in normal games really bad get carried heavily because the enemy team is even worse. Their reaction then often is: "Wow great, my new fav for Ranked!" and then they completly fail their team in Ranked.
I consider myself a pretty decent Leona player (not a "pro" player though), winning about 70% of my games with her - where of the rest percentage most often is not the fault of my lane (especially when I play with a friend as AD Carry). That's why I want to share my insights into her mechanics with players that want to take some advice on this great champ.
At the moment, i'm trying so duo-queue my way up in Ranked, but it's hard as a support player, especially when my queue partner has to take a position different from AD carry. Leona works quite well though, as does Taric.
The guide will focus ONLY on support/tank Leona because I think at the moment this is really the only position she can fulfill in a great way. For top and jungle there are so many other champions that fulfill the role better and using Leona on such a position would be a waste of potential in my eyes (this does NOT mean that solo top or jungleing with her is doomed to fail!).
October 24, 2014
- Updated Items, Runes and Masteries to fit the current meta. I wasn't playing so much Support this Season so bear with me if you see any problems with the builds.
November 24, 2013
- I'm currently playing the pre-season to update this guide with the new items, masteries and tips. Some things are still not final (relic shield^^) so i will not change the builds yet. What I can say is that definitely Leona benefits from the changes. More Gold for supports means you can get more active in lane and better carry your ADC if the lane went not so well (that was always a problem with Leona). As for items one can say that the choice seems to be much broader now. The ward situation is both unfortunate (if you team doesn't understand that they have to ward, too) and good (you can concentrate on items more). Pink wards probably will get changed again, since noe stealthed characters (Eve, Twitch) are quite OP.
November 2, 2013
- checked guide validity against current state of the league
- some minor item changes
June 27, 2013
- changed some items around
April 7, 2013
- changed the build order on some items
- updated some champs from the preferred lane partners section
January 27, 2013
- updated all builds to be S3 compliant
- updated textual description in some points
December 6, 2012
- a first look on the new items
- updated masteries, runes stay the same
- textual updates will come (maybe on the weekend)
October 25, 2012
- some minor corrections
- I have some videos in the pipeline, hope to publish them soon (editing takes so much time...)
August 18, 2012
- switched builds
- edited some parts in the description referring to builds
- added a 3rd build, starting with Boots of Speed
August 10, 2012
- restructured build #1 a bit
- added some item info
July 29, 2012
- wow made it to the top rated guide! Thanks to all voters (except troll vote from random person). This will keep me updating this guide with even more effort :)
- added a second build path and masteries. Those are the ones I currently use and they are very good if you are familiar with the skills and have some practice. The first build is safer, but not as powerful. Remember to choose boots according to the situation.
- updated Twitch and Miss Fortune in laning partners section
- added Blitzcrank to the "laning against" section
July 2, 2012
April 25, 2012
- added Boots of Swiftness and Ninja Tabi to alternative items
- fixed some minor markup-issues
- added alternative mastery page
April 17, 2012
- already 1k viewers, nice! :)
- added the video section
April 15, 2012
- added some versus-tactics. more to come.
- added Corki and Ezreal to the lane partners section
- updated the lane partners section
April 13, 2012
- updated the alternative builds
- updated the alternative summoner spells
April 11, 2012
- this guide was published
Pros / Cons
Leona is a strong Champion, but she still has her weaknesses. This section will focus her strenghs and shortcomings.
- 2 stuns (one of them AoE) and a short root, all on (quite) low cooldowns
- with her shield on, nothing but heavy focusing can harm her (I love enemies focusing me)
- great harass in lane phase with QWE-combo
- ok initiator with Solar Flare or Zenith Blade
- to be effective you have to hit that Zenith Blade ("Skill comes with practice")
- quite weak early midgame if your Eclipse is on cooldown
- you have to have a good game overview (positioning, minimap, warding, enemy items/feed and ability cooldowns) to be an effective stunning threat (again, the practice)
- Sunlight deals 1 (in words: one) less damage to champion skins wearing sunglasses (e.g., Vayne, Surfer Singed and the Commando skins)
The rune page is the tank standard, however I will explain my choice of runes in detail:
9x Greater Mark of Armor
- Pretty standard, probably the best marks for bot lane (vs. AD)
9x Greater Seal of Armor
- Also standard, probably the best seals for bot lane (vs. AD)
9x Greater Glyph of Scaling Magic Resist
- You won't need much MR in the beginning, so we take MR per level here.
3x Greater Quintessence of Health
- 78 additional health from the start. This gives you the power to play agressively early on.
This is the runeset I use for my Leona, there are other possibilities of course. There is for example always the debate about using gold runes such as Greater Quintessence of Gold when playing as a support, but I feel the lack of health in the beginning is never worth the additional gold.
MR per level can be replaced by flat MR if you play against an uncommon support like Lux or Morgana on bot or they don't have a ranged AD Carry.
Why I don't take CDR runes:
CDR is an important stat on Leona, however with the 3 points in Enlightenment and the midgame items - Shurelya's Reverie and Kindlegem - you will get around 37% of CDR (endgame 38.1%), so I feel the runes I picked have more value.
The build features a 0/16/14 page, which is highly beneficial for support/tank Leona. Grabbing
(480g in a 40-minute-game) helps you pink-warding, while
lets you keep up in experience points during the lane phase. Since you can anyway not dive until midgame, you don't really need 21 points in defense. I recommend this build for all people that have played some games with her already.
If you like to play more secure or are new to Leona, you can build a 0/23/7 tank setup with some minor tweaks. This should be self-explanatory:
My recommendation: don't do it. Learn to use your Eclipse effectively and you won't need this.
Build #1: Agressive support build (my favourite). Main focus on mobility and CDR, mana may be a problem if you can't hit your Zenith Blade
Build #2: Even more agressive build, this works if the game goes really well. Focuses heavily on mobility.
Build #3: Defensive build for when a game goes not well. Focus on survivability and sustain.
As I will outline in the section "Team Work" your role as Leona is tanking damage, disabling your foes and protecting the rest of your team. The most effective way do do this, especially in team fights, is by purchasing aura items. But we'll get to this... let's start at the beginning.
2 Sight Wards, 1 Vision Ward and 4 Health Potions
"What? No items on Leona? gg". If I had a nickel... anyway. This works very well and proves to be an effective use of gold. You may not need the Vision Ward every game but I recommend taking it (to counter their pink-warding). If playing against Twitch or Evelynn (jungle or lane), it's basically a must.
Sightstone, Vision Wards and Health Potions as needed
Important things first: When going back, of course don't leave your carry in a bad situation (or throw away ganking opportunities)! Backing after pushing out a lane so that the enemy looses CS on his tower is the best way. Also, wards are very important; you should be able to afford at least one Vision Ward along with Sightstone so you can work out a nice vision and numbers advantage at dragon with your jungler and mid.
Since HoG was removed from the game, the Sightstone has become a really nice and (imho) necessary item. In high elo you may see players not buying it (e.g. Gambits Edward), but you would need an excellent teamplay for that to pay off. So don't expect to get by with that ;)
Back2Topic, you should try to get a Sightstone on your first back, and generally as fast as possible. Because from then on buying Sight Wards should not be necessary. Buy some Vision Wards instead, to counter their warding - especially around drake. Take some Health Potions if needed (you will now take quite a lot of damage if you get hit with Eclipse on cooldown), I feel on Leona the Crystalline Flask would be a waste of money.
From now on, backs can be very situational. Arrange them with your carry. Your next goals should be to get Boots of Speed and the upgraded Ruby Sightstone.
Boots of Speed, Ruby Crystal ( Ruby Sightstone if possible), Vision Wards and Health Postions as needed
Ruby Sightstone, Ruby Crystal (for Kindlegem), Vision Wards and Health Postions as needed
4th and additional backs:
Your goal is now to finish level 2 boots (in most cases Mercury Treads, but don't be shy and consider Ninja Tabi and also Boots of Swiftness according to the situation in the game) and Shurelya's Reverie. Which one I prioritize depends on the game. If having big problems in lane, it CAN be useful to get Aegis of the Legion instead of Shurelya's Reverie first. Anyway, it also depends on when I'm able to bluepill. Also note that backing for Kindlegem (in case you get Shurelya's Reverie or Zeke's Herald) isn't the worst idea once you can afford it. The CDR is worth a lot!
However, there is no need to rush any item now, so I communicate with the carry about backs and try to stay in lane a bit to soak up some xp (I will be around 1 level behind my carry now and I'll try to close the gap if possible).
The next item depends on how the game works out. If my carry or the (AD) top/jungle is fed I take Zeke's Herald, if the team is having problems I get Aegis of the Legion or Locket of the Iron Solari. Later on you want to upgrade Aegis of the Legion to Runic Bulwark, which is a very strong item if the enemy AP carry is any good.
Of course don't forget to buy [[Vision Ward]s all the time, vision is the key to map control and map control is the key to victory. You can ask the other players to buy wards, too if you don't have enough money (lack of assists).
If the games goes on for a really long time, Randuin's Omen, Rylai's Crystal Scepter or Locket of the Iron Solari are viable choices for the last item (remember: you need 1 slot for wards).
Build starting with boots
You can start with Boots of Speed, a Sight Ward and a Health Potion. This will give you more initiation power but you will have to go back earlier for wards and it delays your Sightstone by a good amount. I don't really like this start build, especially since the boots were nerfed anyway.
Other items that work on Leona but don't offer as much utility as the previously mentioned.
Keep in mind that CDR is capped at 40%, everythig above is wasted. Consider buying a different item if you would get over that limit.
Randuin's Omen and Frozen Heart
- Very good items if the enemys AD bursts down your team too quickly, still they are quite expensive so I just grab them when I really need to.
Boots of Swiftness
- If you plan to get Shurelya's Reverie and Zeke's Herald early you may opt for these boots. They offer great chasing and initiation utility, but on CC-heavy enemy teams even Leona should take Mercury's Treads
- This is in fact an interesting item. It's quite costly and doesn't fit into your regular build. However, if you need/want the GP5 from Kage's Lucky Pick, this upgrade is imho preferable to Shard of True Ice.
Shard of True Ice
This item is a bit like Soul Shroud was... kinda meh aura effect, the GP5 is nice and the active can be useful. I still tend to dislike it.
- Very nice active effect, but it's also very costly. Versus a very CC-heavy team your AD better takes the Cleanse summoner spell.
Frozen Mallet and Rylai's Crystal Scepter
- Your top lane and/or jungle should build one of those, AP ratios on Leona are too low to make Rylai's worth the expenses
- If the enemy AD carry is really fed and harasses your lane without the danger of getting killed (for example if he got like 5 kills in first 10 minutes), you may consider to buy these.
- The enemy team is pure AD damage? let them kill themselves while the additional armor keeps you comfy (remember: damage returned is calculated before the damage reduction you get from armor but reflected damage is magic damage so any enemy MR lowers it). If the enemy focus is good though (means they don't focus you) Randuin's Omen and Frozen Heart will be better for your team.
- For now it's OP (League of Warmogs ftw^^). But it will get nerfed soon I guess. Also, you normally won't need that huge amount of HP and it's really costly for a support. Additionally it takes up space without offering team utility.
- Your AP and AD carries should get that if they are focused too much, since you initiate the passive is just a waste and it's not a cheap item.
- In my opinion this item is not worth the money (on support Leona at least), 35 dps is nothing in lategame (earlier you won't have money to buy it)
Banner of Command
- Simply not worth the money, in fact I can't see any champion buying this...
For tank/support Leona there is really just 1 way to go. Basically the skill order is like this:
Solar Flare > Eclipse > Zenith Blade > Shield of Daybreak
with one exception: on level 1 I take a point in Shield of Daybreak (no, you can not skill any other ability if I should not consider you an idiot) and on level 2 I take Zenith Blade to be able to protect my carry efficiently.
After that, maxing out your Eclipse is very important. Every time I can (except level 6 ofc) I put a point into it. Then I max Zenith Blade to get its cooldown to the same amount as Shield of Daybreak (to keep it that way I put the 2nd point in Shield of Daybreak at level 13) and because it damages and marks enemies in a row instead of just dealing (a little) more damage to a single target.
Flash and Exhaust is the way to go.
Ghost and Exhaust is just as viable. The choice here is a matter of taste/playstyle and wether you have another good initiator on the team or not. I like the unpredictability of Flash, but I can see the benefits of Ghost for initiation and chasing down enemies (don't overdo this when you have no vision!).
Flash and Clairvoyance works but if the enemy carry is fed and you don't have Exhaust you may loose an otherwise winnable game quickly. In 5v5 premade games this is still a valuable spell and you may go for it (still at least 1 Exhaust should be on your team).
Heal and Exhaust / Ignite and Exhaust work, too but I'm not a fan. For one, I need Flash to initiate fights or - being infight - to stay longer. Because when you initiate and your team joins, odds are that if you drop below 50% the enemy will not stop focusing you (remember, that's good!) and you can just bait them and Flash away at the last moment (and pray they didn't use Ignite just a microsecond before). On the other hand, your AD carry should have Heal to be able to do some 1v1 baiting when you are walking around the map, placing wards. And Ignite on tank... meh. You don't want to killsteal, remember?
The other summoner spells are just not viable for support/tank Leona.
Favourite Lane Partners
Leona can basically work with every champion that deals a significant amount of damage, however an AD carry is the best choice, of course. Some really shine with her, some are just mediocre. Here's my favourite lane partner list:
- Vayne, the Hyper-Carry. Get her an advantage early and she'll carry any team. Great additional stun if positioned correctly. #1 combo.
- Varus, the Archer. Very nice DPS and has 2 additional CCs (Slow and Root). His Q catches unheeding enemies that want to go back to base just out of sight.
- Draven, the Axe-Madness. Well I think he'll be nerfed soon. For now if a Draven can really play and catch his axes, he's just so much dmg.
- Talon, the Assassin. Though he's not ranged (except his Rake) a well-played Talon / Leona combination can decide the game as early as at the 10 minute mark.
- Graves, the One-Shot-Wonder. His amazing burst damage plus the slow from Smokescreen work very well against most lanes, Soraka and Janna are kind of a counter though.
- Tristana, the Gunner. Great range in lategame and her jump can secure kills or get her away while you distract the enemy. Also, nice burst early on.
- Kog'Maw, the Professional Puker. Nice damage mid- and endgame (esp. vs. AD bruisers), a slow and the most annoying range you'll ever see.
- Corki, the Aviator. You both have a great gap-closer and he deals Tons of Damage™ throughout the game. A deadly combo.
- Twitch - the Sneaky Rat. Since Season 2 he is viable as a carry and works well with Leona.
- Miss Fortune, the Bounty Hunter. She deals a lot of damage and has a slow. This lane works really well.
- Ezreal, the Jumper. A well played Ez will not die in lane. Ever. There are only few combinations that can beat a Leona / Ezreal combo, e.g. Nunu / Caitlyn
- Ashe, the Stunnig Initiator. Her great initiation is very useful for teamfights but her lack of early damage makes the lane not as great as it could be.
- Caitlyn, the Trapper. Good trap placement and her passive can work fine. Still more a mediocre kind of lane with Leona.
- Kennen, the Ultimate Stun Combo. AP Kennen is much more viable in my opinion, though this combo works quite well.
- Sivir, the Boomerang. She deals a lot of damage and has her shield. If you're not ready to push from minute one this will get boring.
- Urgot, the Tanky Abomination. Maybe I've not seen too many skilled Urgots but each time I fight one with Leona + one of my lane partner favs we won... normally this should be a really deadly lane...
A good Janna is a fine counter to Leona. With her Howling Gale she can interrupt Zenith Blade while you are in transit. She shields and grants the enemy carry bonus attack damage. And if everything else fails she uses Monsoon to blow you away - or into the tower if you aren't careful enough. She herself is quite weak though, if your carry has sufficient durability to survive getting hit by the enemy carry, it is not a bad idea to focus her instead. Otherwise wait for your jungler to help out and try to harass/zone them as usual. If you can bait some Howling Gales out by hiding in the bushes, do that.
She's not so stong anymore (since the aura nerf) but beware of the Power Chord early on. She can heal herself and the carry with Aria of Perseverance, so you must be even more agressive if that is possible. From level 6 on you should care that not both you and your carry can be affected by the cone of Crescendo.
Her Infuse is annoying when used on mana-hungry champs like Ashe that then can spam expensive abilities like Volley. The heal from Astral Blessing and Wish is great and can easily bait you. Other than that, she poses no real danger. Just like for Janna lane carefully (your AD should concentrate on last-hitting), wait for your jungler and maybe focus her instead of the carry. In ranked, I would not pick Leona if the enemy team has Soraka.
This is very dependant on how well he plays and how well the game is going for your lane. The attack and movement speed buff from Blood Boil is dangerous for your carry early on but can be ignored later if the game goes well. Careful about Absolute Zero when Nunu is hiding in a bush. You can avoid it if you step away as soon as you get the "Slowed" floating combat text (you will not see the circle if you are not inside the bush!). Ice Blast may slow your carry so it is not easy to killstreak against a lane with Nunu in it.
A strong (healing) support and tank once he has his ultimate. If you can get him before, you can gain an advantage. But there's no cure for his Headbutt. Jungle- Alistar is way more dangerous though.
A strong support with much damage in early game. Don't underestimate her. Since the slow from Glitterlance is a skill shot you can avoid or even bait it (it costs quite a lot of mana). Try to bait Help, Pix!, too. It's expensive and doesn't do much damage to you. Whimsy is a great tool if she uses it right but in a 2v2 it seldomly can turn fights around. However, in team fights it is a deadly spell as well as Wild Growth. It can be rewarding to focus her in teamfights first since she is squishy and has so much disrupting power.
He's a real babysitter. You can play agressive but beware of Dazzle. Don't try to focus him after he reaches level 5 because the passive aura and the passive from Shatter minimizes the damage your (AD) carry can deal.
The Great Steam Golem can be really annoying. Basically, when his lane is winning he will get very strong towards midgame. If his lane is going bad - you shall ensure this - he will be quite useless. Blitz will probably always try to grab your carry, especially if you already have Heart of Gold. So your task is to position yourself such that he can't grab your carry. Don't get grabbed into the tower though...
When he pulls off a grab onto you, consider the situation and maybe you want to go for his carry because Blitzcrank has just wasted all his CC on you. Also don't forget you have Eclipse (you can turn it on while you get grabbed) to mitigate the damage from Power Fist.
I hate mirror matches. But thanks to this guide, you should know how to counter her ;)
Laning against a good Sivir can be annoying. She will not use her Spell Shield unless you zap yourself towards her with Zenith Blade because she knows she can't avoid the zap. Instead she will use it exactly when you try to place your Shield of Daybreak and the only thing that happens is that she gains mana and you get hurt. Playing like that can get refill her mana faster than Sorakas Infuse. Instead try to force her Spell Shield by zapping towards her and not activating Shield of Daybreak instantly. Wait for the shield to come up and back up or follow her until it wears off and stun her then. Do that a couple of times and she'll likely not activate Spell Shield when you zap at her - now you can instantly stun her for an easy kill.
Unless he has blown Valkyrie just moments ago better go for the support if you engage. He'll probably get away anyway. Also, beware of his strong damage and range.
Try to bait her Rocket Jump as often as you can. And don't get kicked into a tower by Buster Shot.
If she stuns you with Condemn you did something wrong. Positioning is key to fighting her. Always be aware of the fact that she is much faster than you when she moves into your direction. Her ultimate Final Hour and a quick Tumble make her invisible for a short time... but you know where she will be going when she's dedicated to kill (your carry). You can land Zenith Blade on her if you estimate the position correctly and directly put a nice Shield of Daybreak in her face as soon as she reappears.
Not much finesse with this cahmpion, just pure damage. A good Graves will dodge at least some of your Zenith Blades with Quickdraw. He's also suprisingly sturdy thanks to True Grit. Protect your carry well and try to harass a bit. In ranked, I would rather try to pick Janna, Lulu or Soraka if the enemy team has Graves.
to be extened soon
Team Work (Laning Phase)
Here comes the tricky part, team play with Leona is not really easy - especially you need to have a good overview of the game. This means you need to keep an eye on many things, most important probably that is which targets you need to disable.
The first 15 minutes you will probably work with your lane partner most of the time though. Your goal as Leona is to protect your carry from harm (your eye is on the minimap very often) and get him fed on creeps and kills while outranging/harassing the enemy bot lane.
In contrast to other supports that just sit in the bush and heal up their partner ( Sona, Soraka) or give a shield ( Janna) or buff ( Nunu), Leona needs to take a more active role - and this makes supporting with her much more interesting & fun than it is with many other champs. Because you cannot heal your partner, you must hurt the enemy instead.
Whenever you have your Eclipse, Zenith Blade and Shield of Daybreak ready (and the enemy is not fed into oblivion or under their tower) you can and should go forward and harass your enemy, even if your AD just keeps farming because he doesn't want to loose the cs. Even if you take slightly more damage than you deal the enemy carry looses cs and you deal a bit of damage which a non-sustain lane (one without a healer) cannot get back as quickly as you can with Philosopher's Stone and Health Potions. Ideally, of course, your AD carry uses the stun to get out one or two autohits. You can time your attacks so that he doesn't loose any creeps.
Use the bushes to your advantage. Outzone the enemy if you can, let them loose cs and even xp if possible. But you must also care that you are not too far from your carry, else the enemy might decide to turn on you (he will probably have boots and be faster than you) and do heavy damage.
With very few exceptions you should not go forward if you failed to hit your Zenith Blade. You are too slow and ranged ADs will hurt you while they just run backwards. Because Zenith Blade is a skillshot and not so easy to hit I never activate any of the other skills until I am in transit towards the enemy. That would be wasting mana in my opinion. Some guides recommend activating Eclipse before to deal more damage, but the better way is to activate it in transit and just follow the enemy until it explodes and then retreat. It will deal damage and be up for another 3 seconds to protect your retreat.
In this phase, warding is key to success even more than in late game. If the enemy jungler is likely to start at the Ancient Golem (and you are blue team), drop an early ward below the ramp into the river such that you can see him coming. If you are purple team you can set it on the edge between tribush and the river. See a warding guide for more tips on this issue.
As soon as you hit level 6 you can almost guarantee a kill even without help of the jungler. Go for it if you see a chance but make sure your lane partner is also on board. Use your Exhaust wisely, sometimes it's better to settle for a support kill than forcing it on the carry and dying in the process. Also be careful about tower diving for now, you'll need the Heart of Gold to take more than a few hits. Don't get Heal-baited!
Team Work (Teamfight Phase)
When you come into midgame you will encounter more teamfights. To be prepared, drop wards at important spots (I will not go ahead and tell what's been told a million times, just read a guide on warding if you're a new player) whenever you have the money to buy them and the time to wander off. Midlane always appreciates additional wards and a warded enemy blue buff can turn games around. Don't leave your carry alone for a long time though, he'll have to play very careful (he probably still can't 1v2 by now) and loose cs. Also he's in danger of being ganked much more.
Keep in mind that you don't deal much damage, so never enter fights when the team is too far away. For the same reason you need to protect your carries, because when they are dead you are as well in 90% of the cases.
In bigger team fights (first ones are probably around drake or the outer mid turret), you need to itentify the biggest threats to your team. Those will most likly be the carries (AD and AP) but which one is more fed? Which one has his/her ultimate ability ready and whose ulti can do the most damage to your team (damage here also means destruct/disable your team, not only flat dmg/dps)? You need to tell your team (or ping) which target you aim to disable before you start a fight. This might not work out if the target is too much behind, then the team must react on what you do (this means you should'nt do bullsh*t in laning phase because if you do, the team will not follow you later).
Positioning is also an important part of the game. If you have a Galio in the enemy team you won't like to fight in crammed places (oh my god how often teams don't get that xD), again warding helps you and your team to get to the battle grounds of your choice. Also, try to avaoid fighting in the jungle if you are up against champs that can surpass walls easily ( Kassadin, Shaco, Shen, Gragas etc.). As Leona you'd need to hit the enemy champion with your Zenith Blade to surpass the wall which is much more difficult.
Stay in fights as long as you can, even sacrifice yourself when you see your team can get 2 enemies for your death if you stun one instead of running away. For your aura items to work you must be in the middle of fights - get involved. Especially when you have Zeke's Herald and Aegis of the Legion you need to fight as long as you can, giving your AD carry a chance to get off as many autohits as possible.
Leona is an ok initiator, but there are way better ones (especially if you'd have to initiate with Solar Flare). If you have Ashe, Swain, Blitzcrank, Amumu or Malphite (possibly there are more, these are just taken as an example) on your team let them do it. Either their initiates are not skillshot-based or they have a higher range, lower cooldown or just break up enemy teams instead of just stunning a few foes. Of course, this is very situational again. So it will need practice.
When you get CDR your stun will become available more often. If a specific enemy is dealing most of the damage (let's say a Malzahar or Katarina with their ultimates) you might still want to keep your stun for them or at least be ready to drop a large Solar Flare onto their heads. If you used your stun and ultimate already you still have Exhaust. Don't forget about it!
Eclipse has quite nice damage. So especially in early game when you see that your carry can make the kill and you have Eclipse in Phase 1, run away from the enemy to grant your carry the kill. On the other hand, when you are sure that your carry can't score, you can try and flash after enemies with Eclipse activated. Got me a kill once in a while (and the enemy carry can't farm while he or his support is dead!).
Zenith Blade pops shields like Sivirs Spell Shield and Banshee's Veil and you will still dash to the target (only the neglectable damage is blocked)!
If the enemy does not expect it, you can use your Solar Flare to initiate team fights (stunning multiple foes at once easily).
See the enemy jungler with low health and a Health Potion used disappear from mid lane? He'll probably try to do the Wraiths before recalling. Ping your AP carry and try a Zenith Blade through the wall.
Eclipse does not break spell shields (any more). But Zenith Blade does. So make sure to hit that, and if you didn't hit don't waste your stun ;)
In this section I will provide some videos (over the time) on how to play Leona effectively. The videos will be made from LoLReplay material because I don't have the disk capacity to record multiple games in a decent quality. Sorry for that, but the gameplay should be visible - and that's what counts.
Video #1: How to procure 3 early kills for your carry
I hope with this in-depth guide to support/tank Leona I was able to show what a great champion she is (though I would never be disinclined to seeing a buff on her as well) and how much utility she has to offer for any team.
Hope to see your Leona on the Fields of Justice soon.
PS: Comments are of course welcome