try to push down on your lead foot and then make a sudden weight transfer to you trail foot. bring you front foot up followed by you back foot. Cody D. is right. its a lot like a skateboard ollie.
the best way to ollie high is to push down really hard on your front foot andthen shift your weight back really fast ontoyour back leg!!!! itwill feel kinda weird at first but it works for me!!!!