I Play Leona as Tanky support, focusing on disrupting and stunning on the enemy carries. Doing so ensures that your team will be able to focus high value targets, survive team fights, secure victory.

Tank runes to help surviving early harass which is where Leona thrives when laning with a ad/ap carry. Flat armor marks, hp per level seals, and mr per lvl glyphs. Movement speed quintessences pair well with the utility masteries.

The only thing I recommend is going back for the philosophers stone when you make that cheddar. Also a potion is users choice, if you think you can survive without do so.

By level 3 let the harass begin. Throwing your Eclipse up, Zblade in, one auto attack then SoDB. That combo will give you max damage output, as well as pair well with your ad/ap carry locking down a target in your zone. Getting that early philosophers will help you stay in lane and keep up the pressure if the situation calls for it.

Maxxing Q, W, R, E -- ult always when available (<-- should go without mention)

Flash cause is OP, and exhaust also works well, clair for the try hards if your team doesn't pick one up.