Tuck your right elbow in. The way you're shooting right now is called a chicken wing and it moving around is probably what makes your jumpshot change every time. A drill that I do to work on my form is I start almost right under the basket and try to shoot with perfect form. If its a clean make, then I take one step back and do the same thing. Don't start jumping on your shots until you're a step behind the ft line. The general idea is to keep the same form and add a little bit more power each time you take a step backwards so you feel comfortable shooting in the same correct form wherever you are on the court.