i don't speak english very good, so i will not really say a lot of things. Leona is a tank without a lot of health but really good control and if you really want to tank you need the twice. So my build is oriented to health and armor/magic resist.

it's the same for the runes, i council health, magic resist and armor, you don't need magic penetration because of the mastery tree.

9 Greater Mark of Warding

9 Greater Seal of Resilience

9 Greater Glyph of Fortitude

and 3 Greater Quintessence of Fortitude

they are so the best for my build.

i've choosen the first tree for secondery skills because i would like to have the magic penetration and so, i don't need to buy stuff with it and i think that's more usefull than the third.

warmog is the most important stuff for my build but it's so difficult to end kill minions in a game with leona so it will be your only difficulty. the other stuff are to make you a big bag of life and gardian angle will save you of your rarely death. At the end, you can buy a little bit of AP but the game is normally already efinish.

if you really want to be efficient and control during a long time when your mates hit in team fight , you can do it :

prepare your eclipse 2 second before the pull

make a solare flare in the middle of ennemy team or a target

pull with zenith blade

eclipse will came and now, you stun him with shield of daybreak

remark : you must up "shield of daybreak" at last because the time of stun is the same in all of the levels.

you sould take health if you don't have an assist who can heal, if you have, take teleport, exhaust, ignite or fortify but you really need flash when you havn't your pull or to escape when your mates let you alone ><.

so, leona is the best tank now because she is op and you sould benefit before nerfing^^.
i think that's a good build because i've won all my games with it since i've bought leona.

I hope it will help you!!