go up and out, instead of just dipping your chest and flipping that way you will have more control and can do it of bigger jumps and grab, also it will alow you to work it into mistys easier.
pop and dive before you throw the flip, then whip your upper body down to finish the rotation, trust me diving off the lip and flipping once your in the air is a lot easier then just throwing straight down, watch how tom wallisch does them or simon i guess, if you dive then flip its a lot easier and steezier