I'd say you have nice, deep, relaxed seat. Your back looks straight.... you look good!
Only two things I did notice was thumbs need to be pointing up, and toes in.... but overall, fabulous!
Yea I was help training him ot get better in Dressage. But he and I showed together and got 1st and 3rd he's a great little pony, lots of spunk and personality as well.