This is a very offensive Leona build.
The early Shurelya's is the best way to engage with your ult.

The massive armor in this runeset has great dive potential.

The ignite is a nice summoner spell on supports. Your adcarry is able to take heal, cleanse or exhaust to save himself.

Pros: You are very tanky lategame and can dive every turret.
With this build you can play protect teh carry.

Cons: If you don't win early game you have to play passive, and this is hard with this build.

If you are on blue side, kill double golems with your adcarry. On purple side go to wolves if your jungler starts red. The Lv 1 boots allow you to permanently engage the enemy adcarry or get away from a gank. You have to play very very very aggressive on Lv 2 because you get a little bit of exp advantage from the jungelcamp. When you hit 6, just try to dive the enemys with the help of your jungler and adcarry. After winning the lane, you are able to roam.

In Teamfights you have to choose:
1. Engage on the enemy carrys. With a R - W - E - Q combo is one of the enemy carry long enough stunned to kill him.
2. Play protect the carrys. With a R in the enemy team and E + Q on near enemys it is easy to save your carrys.