First : This only works for night elves and rogues (maybe druids)
Ok, so you ganked that guy because he ganked your alt and now you know he's there waiting for you to leave so he can continue leveling. You want to gank him so badly...
You sit down after a time and count to 20 or around (so it should look like that you're about to logout), then you push the stealth button/shadowmeld button/Prowl button. 50% of the times (if not more) they ress and you can happily gank them once again!
Did search for it and didnt found anything. And... Is this the section to post such things?: