in the beggining you cant suicide (eventhought you cant suicide in any) just focus on giving most damge with everything you have and that includes your passive, becuase when you use an ability you get bonus attack speed in your next 2 basic attacks and they return 30 energy and try getting gold so u can get the 3 doran blades as fast as possible then focus on other items.

with this build i got fed and was almost impossible to kill and my ed score was 31/11 (i even beat up warwick)

pros
the good about lee sin is that he can hit enemy at tower without getting hit by tower.
lee sin can also do damage like crazy when going on 1v1
he can also see invisible with his 1st and 3rd skill

cons
lee sin's abilities are double abilities so its a little complicated to use
he cant defeat people like trynd becuase they have undying rage taht makes him with 0 hp but cant die so your life steal is useless against him

this runes makes you a lot durable in lane and you'll give tons of damage

this masteries are for giving massive damage and duration in the lane and the life steal is also helpful to your doran blades in the beggining and for your bloodthirsts at the end

this items make you strong enough to kill almost all chapions and your life steal will be massivly unstopable and you will be tank enough to get some towers when doing backdoor

this summoner spells make you defeat someone like xin zao and kog maw by exhausting them and the flash is for going in front of the freaking minions so you can hit the skill on them and for escaping