xerxes - DarkSeer (Jungle step by step)
Dark Seer is such a good hardlane hero because he can farm without being in harms way.
While you prevent yourself from getting damage on the lane, by putting your shells on your creeps or the enemy creeps, you can not avoid getting damage in the jungle.
There are several more advanced tricks but the basic idea is to kill the small camp with a iron shell on yourself while stacking the hard camp and repeat. When the hard camp is stacked 4 to 5 times you can start killing it by putting a shell on a creep.