Lee Sin are a very good jungler but he can lan to its not so hard just use [q] to the enemy then use [e] so you damage alot and hurry use [w] back to minion ore friendly champion.
its not hard but you need to be carefull and its a good idea to play with GANGPLANK ore OLAF its good to Lee Sin with them i ´don't know why its just awesome.

wen its first time you play Lee Sin this build will not help you so much its made to pro there want to kill and help team alot but wen you are noob to play him its sounds stupid but you can first usé power to smash the enemy aeay and so use [w] to get hurry to minion ore [q] to get to enemy minion just say it so you can escape its a good plan you can also use flash ore heal.