This is a guide for an off-tank Lee Sin jungle. I am not suggesting that this build is perfect, it is merely my suggestion from experience in ranked games. Yes, I know this guide is very bland and boring :3.

The runes I use are as follows:
9x Greater Mark of Desolation - IMO the strongest mark, attack damage or crit. is not needed on Lee due to his strong early jungle.
9x Greater Seal of Resilience - Helps you to retain high hp constantly whilst jungling.
9x Greater Glyph of Shielding - Some MR to help you mid - late game.
3x Greater Quintessence of Fortitude - Another boost to your early jungle, allowing you to clear with ease.

A basic 21 - 0 - 9 mastery tree.
Prefer the life steal over crit. chance to boost the effectiveness of your inital vamp. 9 points in utility for the 20% buff duration. Rest is pretty self explanatory.

Basic Lee Sin here - R > E > Q > W
Using E can also be very effective in ganks.

Self explanatory yet again, possible to take ghost over flash if you feel your w can save you in most situations. If you feel REALLY safe, you could also take ignite / exhaust. IF YOU ARE A JUNGLER YOU NEED SMITE.

For my jungling I start at small golems then attempt a level two gank to either top or bottom, depending on the side our team is on. Lee has a VERY strong jungle power so you should be able to go back at your own convenience. I then carry on the wraits then wolves and continue clearing the jungle when possible. ALWAYS give your blue buff to your AP carry or any other champion that needs it. For dragon / baron steals hit your q when it is on around 150 hp more than your smite, activate. smite then ward and w or flash out.

LISTEN REEL GOOD.

Okay, this may take a while. There is no ONE build for Lee Sin nor any core items (par wriggle's, perhaps). Your build should always be situational, but I will list a few of the main team comps you will come across.

Vs. Balanced Team

( Vamp. > Madreds > Boots > Wriggles > Ninja Tabi > HoG > Warmogs > Atmas > FoN > Randuins > Bloodthirster )

Vs. AD Heavy Team

( Vamp. > Madreds > Boots > Wriggles > Ninja Tabi > HoG > Warmogs > Atmas > FoN > Randuins > Bloodthirster )

VS. Full AD Team

( Vamp. > Madreds > Boots > Wriggle's > Ninja Tabi > HoG > Warmog's > Atma's > Thornmail > Randuin's > Bloodthirster )

VS. AP Heavy Team

( Vamp. > Madreds > Boots > Wriggles > Merc. Threads > HoG > Warmogs > Atmas > FoN > Banshee's Veil > Bloodthirster )

• Try always having a ward or two on you so you can use your w to go through walls whilst escaping etc.
• You can use your flash offensively, when ganking try qing onto him or a nearby minion, flash behind him, then ult him into your ally / allies.
• Always get to the centre of the fight BEFORE you use your randuins (if you have it).
• Try to only use your ult in teamfights when you are able to knock up three or more enemies.