You are standing in your stirrups and staring at the ground. Look where you want to end up, and I doubt you want to end up on the ground. Look up, don't duck to the side and stare down.
Sink your weight into your heels and squeeze over the jump with your calf. Right now your are tilting with your knees as a pivot. This means you are not supporting yourself or your horse. Sink down into your heels, open up your shoulder, and look UP!
Your horse is a very nice, looks like a gorgeous girl! Her knees are a bit sloppy, but I think she's making up for you. If you support her and stay off her neck I bet she'll be a cute jumper.
On the positive note, you have a very nice upper body in the flat picture, very straight! Still look up though, lol!