First thing I noticed is that you really, really need to shorten your stirrups at least a hole, possibly two. When you do this you'll be able to more easily get those heels down and have a good base of support. It looks like right now it's hard for you to get up off his back and that shorter stirrup length will help.
You're also anticipating his jump and because of that you're getting ahead of him then coming down too soon and bumping him in the mouth. Be patient. He looks quite capable and I'm sure he knows what he's doing. Get into a bit of a 3-point position and grab onto mane as you go over. Honestly though the best thing for you right now is to look for a trainer to take jumping lessons with. Personally I don't think it's safe nor fair to you or the horse if you're just muddling along on your own. A lesson once a week or once every two weeks wouldn't hurt.
"Always be yourself. Unless you can be a unicorn. Then, always be a unicorn."