I am -A True Kast- a Lee Sin main currently in Platinum 4 /EUW.
I have started playing lee sin every since i was a lvl 10 and have always loved the champion.
I Have over 800 ranked in games in season 3 , 4 and 5.
I have build up a lot of experience with the champion and i am currently on 475k mastery points with a 54.5 % win rate on Lee .
It took a lot of time to master Lee Sin + knowing his strengths and weaknesses .
I Hope you enjoy Da guide! :P

( My excuses for bad spelling , i'm not English and my computer automatically translates english words to my country language.)

STARTING ITEMS - You always want to start off with 3 health potions if you are planning on going for an early gank. The reason being , you will most likely just like the enemy jungle start off at bottom side and end at your 2nd buff giving you level 3. both of you are topside and 1 of the top laners should be overextending . Both of you will be going top expecting each other . There will be a 2v2 fight and because of the 3 health potion start you are at full health and ready to go . If you would have picked the 2 dose potion you would not be at full health leaving you at danger of getting killed.

TRACKERS OR SKIRMISHERS -
You pretty much want to always build trackers knife but there is 1 exception making you HAVE to build skirmishers.
Skirmishers is a MUST have against champions like xin zhao , rengar etc.
These champions also build skirmishers leaving you unable to duel them unless you buy it yourself.

BUILD - This is the build i use for pretty much all my lee sin games. It is a prefect mix of Damage and Tank. You can Insec with this build , u can kill AD carry with this build . You can peel with this build . You can do a lot with it.

WHEN AHEAD - whenever you are ahead you don't need to build these items. You should only build these items when you are convinced that you will be able to kill a high priority target a lot in the upcoming fights. Youmuu's active is practically worthless on Lee but the 60 AD and 20 armor pen gives you a lot of damage.Ravenous hydra also gives you a lot of damage , not as much single target damage but a lot of AOE damage combined with your E.

BOOT OPTIONS -
I would recommend pretty much always going for mercury treads because of the tenacity , just like with any other champ CC will hinder you a lot in team fights and maybe even 1v2's with the enemy bot lane .
If the enemy does not have a lot of CC u can go for a boots of swiftness to reduce slows and also make you a bit faster.
Ninja Tabi's are pretty much only recommended against hardcore AA champions like Tryndamere ,Olaf etc.

LAST ITEM - All depends on who you are playing against and what is happening in the game. If you are against a team with good pick and engages you might wanna go for the banshee's to protect you against those cc spells.
If you find yourself diving into the back line a lot i would recommend building a sterak's because of the extra AD and shield that can be HUGE at times.
If the enemy has a lot of cries and/or not of AD damage i would recommend building randuins.
Randuins can also be used for peeling your AD carry.

+ High mobility
+ Strong early game ganks
+ High outplay potential

- Hard to Master
- Extremely weak late game damage.

You want to start off with the Machete and 3 health potions and go to the camp where bot lane will give u a leash . Do this because top lanes give ****py leashes that will leave u at half health.

ROUTE 1 - early top/mid lane (counter)gank
Start off at your bot lane camp and take the 2nd buff , walk to the next buff and kill it giving you level 3 and look to make something happen top/mid.

ROUTE 2 - level 6 rush
Start off by doing a full clear of all your jungle camps giving you level 4 , try to get a gank off and go back to buy items and do another fun clear.

ROUTE 3 - the early bot lane gank
Start off by getting your bot lane leash and doing the most nearby buff.
now clear the most nearby camp and kill the skuttle crab near Dragon .
Go to bot lane to get a tank off.

I would always recommend going for route 1 since you are with this route following your enemy jungles route and this way you can get a countergank off which is ALOT better then a normal gank.
Route 2 is for rushing level 6 so you can gank bot lane efficiently .
Route 3 - I would never recommend because an early bot lane tank almost never results in a kill , since the enemy bot lane have 4 summoners to keep you from killing them .

In this build you will see that i took Strength of the Ages above the Thunderlords Decree.
The reason for this is because lee sin has to keep up with the tank meta that has been going on for ages. I still build Lee sin Ad at the early stages of the game ( AD jungle item black cleaver etc,) How ever u will notice that if you take thunderlords for more damage u will fall behind in the mid game and get easily killed at 3v3's 4v4's etc.
Thunderlords will only be good when you are playing against very weak champions early , if this is the case , you are gonna have to shut the enemy jungle down early or else he will become stronger than you at an earlier point in the game .

As for Runes , you can change them up. Runes are about what you prefer .
I would recommend going for the armor seals and AD and Pen marks.

Now that you know what you can and should do in the early game it is time to talk about the late game .
In the Late game there are only few things you can do but if you don't do these few things you will lose.
The most important thing is to maintain vision control at BARON and ELDER.
If you do not have vision control on these objectives you will have a high chance of a loss.
i ALWAYS stay near these buffs to be able to steal them or keep the enemy from doing them.

TEAMFIGHTS - The first thing that will come to your mind is INSEC , once you master this move you will have an advantage in the late game but it is not always the way to go .
I have won a lot of games because of me kicking an enemy AD carry but i have also lost games because of me failing. There is a simple way to play in the late game team fights that will make your chance of winning a lot higher. PROTECT YOUR OWN ADC , yes i know ur ADC might be **** , and in that case you should try to INSEC kick . But when the enemy has a savior and you have a vayne . Who do you think is stronger....
If 1 of your carry get killed make sure you DO NOT run to base , instead run to baron or elder and try to steal it . I always try to be 1 step ahead of the enemy by hiding somewhere near and coming when i am able to steal the buffs . If you run to baron or elder but the enemy are looking to end the game u have plenty of time to recall .

You can fully analyse this guide and watch tons of lee sin montages but in the end it all depends on experience, i could have never made this guide 1 year ago because i was simply lacking experience .

The best way to learn Lee Sin his mechanics are in fun Normal games with friends!
Practice his moves and u will master them in no time .

If you have any questions or need help you can add me on EUW server .
My name is A True Kast and will happily help you .

Hope you enjoyed the guide , and Good luck learning Lee Sin