RE: how can i get better groups?
looks to me that you may be flinching when you shoot
do you know what blind bail shooting is?
get right up to your target draw aim close your eyes dont think about anything then release the arrow keep thearm in position but let the bow fall forward on release of the arrow. If you dont have a wrist sling get one you need one.
do a search on blind bail shooting here you will find out what the benefits are using this technique