First is hands, get a complete hold on the reins, not tight, but your hands look way loose to me. Straighten your wrists and bring your thumbs up to ctreate the elbow-hand-rein-bit line. Hands will tilt at a 20 degree angle, so thumbs not straight up and down. Also your hands are moving a lot with your horse's head in the video. Work on stabilizing your core to help prevent this.
Next is legs, I notice you lift your entire leg to put your heel into him. Also that he seems to be ignoring your cues. Work on stretching down into your heel and not lifting it, instead wrapping your lower leg around his barrel.
Your shoulders are rolled forward into a very defensive looking position. Your arms are very busy, instead of moving your whole arm get your hands in the correct position at the whither and use your wrists and fingers to make those same movements.
Just a quickie sort of critique for you.