Herrow ^_^ This is my first Mobafire build so i don't really know how to get it to looks all awesome but i'll work on that C: but I hope you can understand how my build works. I've played about 400+ games with Lee sin.

Lee sin is a very aggressive early game champion. He falls off late game but your early game is extremely good. His damage is high and his ganks good because of his gap closers. Lee sin can carry, but not a whole team. Your team needs to be able to carry as well as you to win.

Sonic Wave: Lee Sin projects a discordant wave of sound to locate his enemies, dealing 50/80/110/140/170 (+90% of bonus Attack Damage) physical damage to the first enemy it encounters. If Sonic Wave hits, Lee Sin can cast Resonating Strike for the next 3 seconds.

Resonating Strike: Lee Sin dashes to the enemy hit by Sonic Wave, dealing 50/80/110/140/170 (+90% of bonus Attack Damage) physical damage plus 8% of their missing health.

Cost 50/30 energy

Cooldown 11/10/9/8/7 seconds

Lee Sin's Q is very useful for closing a distance between him and his enemies. Have you ever tried to gank a lane where you land sonic wave, jump to them and then they flash? well instead of using Resonating Strike once you've landed sonic wave, wait for them to flash and then activate the second part of Q. Even if you've tagged them with Sonic wave, they sometimes still flash and that's when you use Resonating Strike. It basically ensures a kill because they've used their escape.

Safeguard: Lee Sin rushes towards a target ally, shielding them both from 40 / 80 / 120 / 160 / 200 (+80% per Ability Power) damage. After using Safeguard, Lee Sin can cast Iron Will for the next 3 seconds.

Iron Will: Lee Sin's intense training allows him to thrive in battle. For 5 seconds, Lee Sin gains5/10/15/20/25 lifesteal, spell vamp, and armor.

Cost 50/30 energy

Cooldown 8 seconds

Range 700

This ability I find is one of the most useful in the game. You can juke your enemies by turning around and jumping past them to an ally minion. You can pull off sick escapes if you have your W up. This ability works extremely well with sightstone, wriggles lantern or just a ward. A useful way to gank with this ability is when the enemy is going for a last hit, jump to the minion they're last hitting and tag them with sonic wave, wait for them to flash, then resonating strike. If they're melee jump to the minion they're about to last hit tag them with Tempest/Cripple and sonic wave when you have an easy shot.

Tempest: Lee Sin smashes the ground sending out a shockwave that deals 60 / 95 / 130 / 165 / 200 (+0.6 per bonus Attack Damage) magic damage and reveals enemy units hit. If Tempest hits an enemy, Lee Sin can cast cripple for the next 3 seconds.

Cripple: Lee Sin cripples nearby enemies revealed by Tempest, reducing their Movement and Attack Speed by 30 / 37.5 / 45 / 52.5 / 60 % for 4 seconds. Movement and Attack Speed recover gradually over the duration.

Cost 50/30 energy

Cooldown 10 seconds

Range 450

This ability is very useful for getting away and chasing enemies. When you're getting chased and they get close to you, use Tempest/Cripple and slow them down, and if you're chasing Q into an E slow's them down for an easy kill.

Early game before your giants belt/black cleaver, you're quite squishy, not to the point where you can be one hit but where you're not tanky enough to soak in damage for your team. After your warmogs you should be able to stick on their carries pretty well.

Dragon's Rage is super useful skill for ganking and quickly killing someone if you have to get out quick (not last hitting with it because you want the kill), such as if you're roaming in the enemy jungle and you run into their jungler, you don't want to stick around there for long since there should be at least 3 people coming to help their jungler, so if you can quickly kill them and get out before they come help, you should be saving yourself a death. Your ulti can also be very useful for displacing someone on the enemy team. Q,Q into a flash behind their ADC to kick them into your team can win you a fight since most of their damage is gone.

Items to never get,
Wits End: Never get this item because Lee Sin doesn't need attack speed because of his passive and the magic resist is basically just getting a hexdrinker, but more expensive.
Frozen Heart: This item is quite useless for Lee Sin because most of the gold is used to get the mana, which is completely useless on Lee Sin. CDR isn't needed on Lee Sin either. I recommend getting an Randuins Omen instead, as you have use of everything in it.
Berserker Greaves: Like I said, Lee Sin doesn't need attack speed because of his passive and Lee Sin doesn't actually need attack speed anyway.