If you've never played Lee Sin
If you've played him a few times
or even If you're a Lee Sin 1 trick there is most-likely something new you can learn in this guide

If you're new to Lee Sin let me introduce you to him. He's a high damage high mobility offtank who excels in dealing burst damage in the early game securing picks mid and late game and moving swiftly through the enemy team Insec-ing high-priority targets into his team. Lee Sin is a blast to play and main. I've been playing him for over a season now and I've gathered 110,000 mastery points with him and a level 7 mastery and I am nowhere near done playing him.

Somewhere between level 3 and level 5 you should gank atleast once. Lee Sin's early game is devastating and not taking advantage of it can cost you the game. Gank a lot camp if you have to play mind games with your opponents. If you gank someone and they get salty in chat camp them they are prone to getting tilted and throwing the game. Make sure to make the enemy team's lives a living hell. Camp gank give vision to your team deny vision to the enemy team counter-jungle make them get tilted to the next dimension. There is nothing worse than being beaten by a good Lee Sin cause you can't say he's a noob champ you can't flame the best you can do is call him a smurf which only flatters a good lee Sin.

Lee Sin has no verioty in summoner spells you ALWAYS should take flash and smite as long as you're going jungle.

Everything is explained under the different build paths

Skill Max Order goes Q,E,W. I used to go for Q,W,E but E does a lot of damage when you max it and the life steal on your W is mainly used on jungle monsters so mid game you don't need it that much.

Thunderlord's Decree makes Lee Sin's early duels devastating. Wether you will fight the enemy jungler over Scuttle Crab or you gank a lane your Q,Q,AA,E,AA,E,AA combo is enough to 100 to 0 most squishy laners. Sorcery is objectivly better beacause most of Lee Sins early damage comes from his abilities rather than from his auto attacks. Fresh blood comes in handy when ganking as you deal even more damage with your basic combo. Natural talen is better than vampirism cause Lee Sin has build in Vampirism in his W second active. Bounty hunter is better than Battle Trance since Lee Sin's fights rarely extend up to 5 seconds but Double Edged Sword is an option if you want an even riscier playstyle (I personally go for Bounty Hunter). In the Cunning tree Wanderer is good for getting from lane to lane allowing you to gank faster. Runic Affinity is great for every jungler but Lee Sin benefits from it grately since red buff on lee sin makes his ganks even stronger and even harder to escape from and Runic Affinity just prlongs the red buff duration. Merciless helps you finish off enemies and helps for early jungler vs jungler 1v1's. Dangerous game helps you get back to jungle farming or ganking by a bit but it doesn't really have that big of an influence but it is better than Bandit since Lee Sin rarely sticks around on a lane for a long time so taking advantage of Bandit is almost impossible. Precision helps Lee Sin deal with tanks since he gets Black CLeaver fairly far into the game so shreding tanks is a bit of a hard task but Precision helps with that. And finaly Thunderlord's Decree makes Lee Sin's early damage even higher his burst even faster his 1v1 duels even stronger and it adds a nice bit of damage that laners don't usually account for.

For runes I take flat AD for even more burst in the early game and some Magic resist and Armor for a bit of survivability

Try to gank as much as you can and get either yourself or your carries fed.
***IMPORTANT TIP*** : Try to do as much damage to the turrets as you can pushing early game is crucial since Lee Sin falls off in the late game.

Oh boy! We've made it it's late game now you're falling behind and you're mainly dependent on your team to carry you. Try to build tanky and stil do some damage or try to use your ult to get an enemy carry in your team or you can use it to peel for your carries depends on the situation you can decide I guess.