Keep your eyes up! Look at a place straight ahead of you (to eye level) and look there (that's more when you're going over a jump).
Your lower leg is slipping forward a bit (almost like a chair seat) -- a lot of people do this, even more when they're trying to slow their horse down.
I'd also like to see you bend your elbows a bit more. You seem a bit stiff...
But, lovely mare! I love her coloring.