The reason I am making this build is because all the other builds for lee sin are all about jungling and i have found a different way to play him. I almost always end up with over 15 kills and only like 3 to 4 deaths so obviouly im doing something write.

Stay in lane as long as posible use Safeguard / Iron Will to gain health back that is why you get that ability and when you can break off and ether gank or go get red buff. Make sure if they are pushing you back to the point of they are attacking your turret use Sonic Wave / Resonating Strike the right after use Tempest / Cripple and if you can get in front of them and knock them back towards your turret with Dragon's Rage. This will also help your team to rack up the kills. When i start getting low on health at about level 7 you can go into the jungle and gain back health from ether the wolfs the golems or the wraiths.

Pros:
He is a very good ganker if you can hit Sonic Wave / Resonating Strike
He has masive life steal from this build
He is a good pusher
Doesnt use any mana

Cons:
He is squishy in the begining before getting his life steal
Some what easy to over play
Difficult to learn how to use his abilitys well

With lee you can take his ult and kick a enemy champion into other champions that will knock them up and will do masive amounts of damage. A trick with his ult is you use Sonic Wave / Resonating Strike, then Tempest / Cripple after that run infront of them and use your ult backwards and get them into your team to get the kill. but be carefull cause when you run in you can run into the other players on his team. Also make sure to use his ult and dont save it cause the cool down is not that long on it.

The reson for flash and ignite is that if they deside to gank you cause you are too strong to face 1v1 then you can flash out of danger. And the reason for ignite is for if you cant kill them and they are right next to the turret and low health you can just use ignite and it would be alot more effective cause he is very good at getting in and out of danger really fast other thing you could get is ghost to speed up getting back in lane or running from danger. The other one you could use is exhaust to slow them down so you can land the perfect ult.