1.)Generally the "early gank" is level 4, coming at about 5 minutes, depending on jungler. Don't gank at 3.
2.) Max your E first. You need all the slow you can get.
3.) Lee Sin is a control jungler, but not a counter-jungler. Before you go into your enemie's jungle, clear camps first and check to see if a gank is available.
4.) Generally you need to use the slow from redbuff + the slow from E to hold an enemy for a gank.
5.) If you can't get a kill, that's ok. The point is to force the lane to waste flash/ghost/ults etc. so that your teammate can win the lane more easily.
6.) Because Lee Sin won't be getting as many ganks, he needs a HoG to offset his roam. I recommend getting one after Madred's/boots 1, and before wriggles.
dont listen to this guy...
lee sin is the most flexible jungler in my experience
havent had too much experience w/ trundle to speak but hes up there too, phoneix udyr too
lee sin can pretty much start anywhere except red i think
which makes it really hard to counterjungle and lets you counterjungle very easily
what i like to do if i know they start at blue is to take dbl golem>wraith>wolves and then grab Q and walk over to their red, they should be fairly low and red should either be done or at low hp, there youll either smite steal or just kill him
might not work against a faster jungler, but that hasnt happened to me yet
or you can just steal wraith/dbl golem camp, its one or the other if you start w/ vamp scepter
not sure if you can take both w/ cloth armor + 2pots+ward
if they start @ w/ vamp scepter, you can start @ dbl golem preferably w/ leash and then steal their blue although its very risky
you only skip Q at lvl 3 if there is no way in hell youre ganking
it slows you down couple of seconds really
you can even grab Q at lvl 2 and still be fine
DONT MAX OUT E FIRST unless i guess your team really has no type of cc
if you try and counterjungle mid game, always carry wards w/ you
jumping to wards+flash = unkillable