My name is skitskit, a Platinum tier Jungle main on EUW. I've been playing Lee Sin from the early beginnings of Season 3 and used him to get into Platinum in Season 5 and 6 on my main account. Lee Sin is a great and strong Jungler to carry whole teams in lower rankings and a good initiator in higher elos.

This guide covers different Itembuilds and playstyles for Bronze->Silver and Gold->Platinum.
For the lower rankings we are using nearly full AD Builds to get the job done.
Higher elos need more tankyness while doing good damage too as Lee Sin.