Hey guys, first guide ever, and i'm just going to keep this simple but in depth, so no one gets confused :D
anyway i'm Shadowstepambush on LoL lee sin has been my main for a while and i think i've perfected alot of knowledge that really isn't shared with people.
Not much to say in the intro except Lee Sin is probably the best jungler if u skill cap him.

The runes I run aren't really intricate, it's actually very standard but i find it to be the best way to play Lee Sin, he has his passive so attack speed isn't necessary and all that flat AD makes his early game stronger, the Armor helps him stay alive during ganks, and i've had a few times where i would've died without them, and the MR helps mid and stacking to late game.

Masteries are more preference when I jungle I like to regenerate my HP and lifesteal, but some people like having more HP to begin with

Items, when you pick your items it's really important to think about what you're going to be doing and how you will effect the game with your items.
the items you pick will almost always be limited too
Frozen Mallet
Bloodthirster 1 - 2
Last Whisper
Randuins Omen
Maw of Malmortius
Wriggle's Lantern (duh)
Black Cleaver (this Synergizes so well with your passive, it's like so scary)
Atma's Impaler
All other items are mostly situational, it really comes down to "Did i kill alot of people?" "Am i not getting enough gold from ganks?" "Am I going to carry?" alot of the time you will carry early and mid game, unless you do it wrong.
Anyway Situational items (Usually if you're doing bad)
Warmogs (yay hp)
any armor items such as
Thornmail
Frozen Heart (wait what?)

You should always max you Q first, unless you're laning and u can't handle your opponent you want to block last hits you can max W, maxing E isn't efficient even though it's damage is massive, and something people don't get is that it's magic damage, so even though they build so much armor, you'll fly toward them and nuke them anyway.

Obviously spells
Noob Sin = Smite Flash
I'm laning = Ignite Flash
Pro Sin = Smite Exhaust

Basically, you are doing insane burst on a single target at the same time ulting which will cause a malphite effect (Knock everyone up with your ult) and do INSANE damage especially if you have 1 bloodthirster stacked.
If you fall behind and can't handle pro sin, go to tank sin and just eat everything while your ADC just 2 shots everyone,
your biggest focus is their ADC but if you get positioned ruined, always JUMP WITH YOUR W back to your ADC and instantly E everyone around him/her. Your Adc > their Adc
If you play Lee Sin properly you can easily QRQ and it will kill an adc no sweat.

Ranked play is quite simplistic, help your team help every lane, die for your carries.

Insane early game damage
Can't die, unless locked down
(CC)
extremely strong ult damage
ult also works like a malphite ult


Can't tank that well
only good in very specific scenarios
main abilities hits minions
ult sometimes doesn't do enough damage and if u didn't Q before they escape

A really important thing to keep in mind is Lee Sin's Passive, make sure to auto attack twice between each activation of an ability to clear camps faster.
Jungling route, there is one route i take, the best route existant,
You go wraiths at 1:40 clear them before 1:50 about because it takes you a while to walk over to Red buff since you know (cloth armor)
once you're there, get a leash if you can if not just kill it anyway, but you'll lose a couple pots. after that just start doing your lee sin walk over to blue buff Q through the blue buff wall and fly in,
after clearing blue buff you walk up the river to the enemy red buff, and go afk
you see the enemy and u just chill there as they attack it, and if they're not Warwick you can just combo them and they'll die instantly, flash if you have too, FB really boots moral to the team and you get gold :D

You will be the crazy dude flying all over the place
Literally,
Jump to adc as fast as you can, if fight isn't goin well or if you see someone going down jump to your Ally, refocus on his target to help him live, if you can refix your aim on the enemy adc and drop him, when playing lee sin it's important to KNOW WHEN TO BACK OFF
When you land that Q your first though is "OH YEAH FREE KILL" then fly in and you're a dead blind monk.
when you land Q don't just go in you're not the initiator (Unless you're unkillable tank sin)
but there's gonna be times when it's good to just go nuts and go kill someone, like in the scenario you land your Q on the Enemy adc and your team is a little bit away, you fly in execute the carry and jump to an alli barely living with 400 hp, this has happened to me, and i've actually gone back in before lol, Lee Sin is pure clutch when it comes to skill cap.

You farm minions if you aren't doing well
You farm champions if you are, not much you can say
but if you're laning you just block last hits with your W (really hard to time unless you're playing against AP mids)
and last hit and try NOT TO USE YOUR E unless you have too.
It'll push the lane so hard.