This build is designed to balance Leona as a tank and AP disabler and give her some extra burst to help do some damage in skirmishes. It takes advantage of her W Eclipse to top off her armor and MR while also getting some damage done with it. The AP in the build will add about 30% damage to all of her abilities, and the Spell Vamp from masteries gives her some more sustain in lane.

This is my first go at a guide, so please let me know what can be added in/taken out/discussed more to make it better. Leona is definitely one of my favorite champs, and I hope she will be one of yours too.

This first version is just to get the basics laid out, and I will be adding more depth to it as I get time to do so.

Pros:
This build has a bit less HP than most Leona builds I have seen, but it takes advantage of the bonus 70 armor and MR from Eclipse which will be up a majority of the time thanks to the CDR of the build (6 second uptime on an 8.4 second CD). These bonuses put you right at diminishing returns for both of these stats.

This build also has a lot of utility and capitalizes on Leona's burst damage. The proc from Lich Bane means that you will be doing around 600 damage on the auto-attack following activating her Q Shield of Daybreak Additionally, this ability is down to a 4.2 second CD with the other items in the build.

The active on Deathfire Grasp will help you out if you get caught off guard alone and will also help level the playing field with other tanks.

Cons:
Obviously, taking away from a tank's health pool will diminish their ability in that role, but Leona will still have an effective health pool of around 7400 HP thanks to armor and MP (her actual HP will be around 3500, which is still pretty solid)

Other than the tenacity from Mercury's Treads you don't have as much survive or escape as usual with Leona, but this is slightly made up for with Flash which has a lowered CD from masteries.

I chose to go with Flash and Teleport so that I can be available for my team when and where they need me. Teleport helps with getting back into lane early game and late game gets you into a lane to help your carry if they get jumped.

When farming creep waves, you want to activate Eclipse early enough to catch as much of the creep wave as possible. At max level, this ability will devastate a creep wave really quickly. It is important to position yourself in the thick of the wave so that you hit as many creeps as possible.

For early game laning, this positioning will also help you regen some HP because of your spell vamp from masteries.

This build works amazingly well with any other champ that also has a stun or a toss of some kind. Volibear I have found is an excellent laning partner for early game because you can bait people in for him to toss into the tower, then you follow with your stun. Easy money.

Also to consider is someone who can trigger your [icon: Sunlight] debuffs on the creep wave. Ryze and Volibear are both great for this, but really so is anyone who has any kind of an AoE that is easily spammed.

As far as ganks go, you want to lead in with Eclipse up then charge at a weaker opponent with [icon: Zenith Blade] While it lands, hit Shield of Daybreak to land the stun right when you get to them. Since you will have hit with Eclipse you will be buffed up on armor and MR and should have a good chance to run out again if you need to.