good drill is to stand 1 step away from foul line
get the ball swinging and 1 step to the foul line, no knee bend, just swing and step, let it go.
virtually impossible to muscle this drill, keep at it until you can repeat that "feeling" of a loose armswing and loose shoulder.
i still "help" the ball from time to time, but not anywhere as much as I used to.
Takes a good coach, watching video of yourself and lots of practice.
Let me follow up the practice comment with "lots of practice with the proper technique"
practicing bad habits is just that - bad.......