When you are about to go over the jump try finding a place on the wall to stare at like a scratch or chip.If you are out side look at a leaf,tree or even just a fence post.Hopefully this helped!
I agree with Gabbie. I use the horses ears kinda like a sight and it helps me from looking at the ground
My trainer always told me to stare at a wall ahead of the jump
I try to concentrate looking between my horses ears :)) this helped me a lot