today i went out and learn hippykillers (at least thats the one i think i was dooing)
they actaully ended up being a lot easy then i had imagine, and i'll wlak you through how i figured them out.
first just find a nice box, i'd suggest a flat down, or something that you can get on from the side. now come into like your going to get on urban style, then instead of hopping on with both feet, just lift your outside foot and pop off your inside foot. ( for me since i grind left foot forward, i'd be lifting my left leg up and onto the rail, and givving a little hop off of my right leg.) I found the easyiest way to work up to it was to go slow and put your hands on the rail as you were getting on to start out with.
At first i had some problems because i kept just sliding out to my hip, but don't worry you'll get the feeling within a little bit. I ends up being that most of you weight is on your front foot (for me left) and the outside of your back boot.
hope that helps and good luck!