Pop Shove-it

I have been trying to learn a trick called a pop shove-it. It is a very dificult trick where the skateboarder must scoop the board with his back foot and make the board spin 180 degrees in the air. I can get the board to spin 180 in the air but it either goes out too far in front or too far off to the side for me to land on it. If anyone can help me, tell me how to keep the board under me.