Leona is typically found playing the support role at bottom but her true potential is yet to be unlocked.

This build is a fun build, people you verse will have never seen a scarier Leona. This build can place you either in the jungle or at top lane, preferably top lane.

Pros:
-High Burst
-Tons of Damage
-Good gap closer
-CC and stun's
-Offtank
-fun

Cons:
-not as tanky as other Leona builds
-Is quite slow, especially if you miss your E spell
-people will get mad at you because you're trying something new, prove them wrong
-will struggle against certain top lane's

known counters:
-Olaf
-Kha zix

See how scary and how much damage you can do once you've acquired these objectives watch your enemy melt!

THE BURNS

items:
-Spirit of the Lizard Elder
-Sunfire Cape
-Liandry's Torment

Buff:
-Red buff

Spell:
-Ignite

Enemies will feel reluctant to go near you as you could pounce on them at any given time with E and set them on fire!

Easy to farm creeps with the items :D

Aside from the core burning items of which you're likely to replace spirit of the lizard elder if you have an incredibly long game. Here are some viable options that you could choose once obtaining:

Core 3 burning items:
-Spirit of the Elder Lizard
-Sunfire Cape
-Liandry's Torment
-and you're choice of boots recommending Ninja Tabi or most likely Mercury Treads

The Burning items synergies well with your spells and make you scary to fight, an engagement or even being touched by you causes the enemy to suffer from several DOT effects, especially if you decide to ignite them and also acquire the red buff.

Each of Leona's spells don't do damage over time effects so each spell will trigger Lizard Elder and Liandry's. Other considerations for items could be:

Trinity Force: Tons of Damage, good utility, speed, spell blade effect and critical strike.

Rylai's Crystal Scepter: All your spells will now slow in addition to damage over time, makes you more tanky and will double the damage of Liandry's Torment.

Guardian Angel: The build has a considerable amount of health, this will make up for lacking resistance

Randuin's Omen: When you're team really wants you to be that much more tanky, good utility. Note: Activating randuins omen with your W spell will improve the slow duration considerably.

Take your runes with a focus on AD for easier creeping at the start and duel potential other considerations to add to this of course would be:

Armor- More duel potential
Mana Regen- Need to be able to cast your spells
Essential- Magic Resist per lvl blue's

Take your masteries how ever you like based on what you think would work

Try it out, it could change you're opinion of Leona. It's incredibly fun to play and hilarious to scare people with, both teammates and enemies.