This is my Leona Build
Hope You Enjoy

The only time you should farm is when you think your adc needs more health than he/she has because with the Relic Shield you execute minions under a certain amount of health to heal an ally champion for a specific amount of health based on your max health

In order for you to be successful in bot lane you must have excellent communication with your adc
Because in some players eyes one kills lost is a loss, (but if played right it isn't a loss)
But you have to have excellent communication, unless you two are in a duo queue ranked match and know how the other plays and are excellent at working together...But if not talk to your adc ask when you two are gonna engage, ask for help from your jungler if you get behind, Also is an awesome tank so don't be afraid to initiate some team fights late game

has few unique skills, but let us name them first is her q Shield of Daybreak Leona rams her shield into an enemy's face and they get stunned... Great right?, but then there is her e Zenith Blade this ability roots the LAST champion in its line and Leona pulls herself towards them giving her enough time to just [ability=Shield of Daybreak] them in the face, her w Eclipse is awesome when engaging she gives herself a bonus in armor and mr for a few seconds then the boost explodes dealing AoE damage, Lastly comes her r Solar Flare which is a very easy ult to hit and it slows enemies if they aren't directly in the middle of the cast area, but if they are they get another stun straight to the face

In my opinion Leona's best combo without her ultimate is start off with casting Eclipse then immediately Zenith Blade to your target to lock them down and finally use your Shield of Daybreak just so your adc might grab that kill.