I took a snapshot of your jump, and I would say to
-Drop your heels- They're a little blurry but it seems like you could drop them down a bit
-Keep your elbows to your side and I would say to give a bit more of a release
-Roll your shoulders back a bit
-And finally, keep your head and eyes up! You go where you look, and if you look at the ground then that's where you're going!!!
Overall, very good, I would also have to agree with the others that this jump is a major safety hazard, since if pony hit the rail it may not come loose. I would try two milk crates instead of just one...
Intermediate Rider~Learning Equitation and English Pleasure~Interested in Eventing
A horse will tell you everything you need to know about him, if you listen.