Alot of low elo players like playing Lee Sin, i'm not against it at all, but if they/you wanna play him you gotta learn how to gank, if you're red side start topside krugs, smite krugs proceed to Raptors(Kill smalls first) go back for red smite it, look for a lane to gank. If you've found a lane to gank start out by asking your laner to bait them, Or maybe ask them to stop pushing.

So, you should probably know that Lee Sin falls off late... ALOT... so if you're in the late game, set up baits pick offs or split push different lanes. It might seem simple, which it actually is.

If you're a low elo lee sin (Bronze - Low plat) I would recommend to you to start of learning "Kick flash play" basically you r them right as you use your r you flash behind them
This is an easier version of the Insec kick (Consider doing this in bot games before going online)