What type of advice are you looking for it seems like you are shooting pretty good, where you can go hunt. If you are looking to tighten your groups then I would recommend filming yourself and looking at the video along with a qualified coach to see what you can improve on.
Check out videos on shooting form on youtube. I have personally been taught one-on-one with mobow or Moebow who has several videos on rotational draw. Look one up then look at the others that he has posted. 3″ groups at 20 yards is pretty good shooting, well within the realm of hunting accuracy. You are doing well if that is your consistent 20 yard group size.