Here's what always helps me:

The best thing to do is only and I mean ONLY shoot three arrows at a time. I think what you're doing is developing bad habits by shooting six or more arrows at a time.

Here's what you need to do. When you're shooting you should be focused soley on the target and nothing else. When you shoot and your pin hits the target the release should be a natural reaction. You shouldn't slap it, it should just go off.

Second follow your arrow to the target. The best way to do this is to shoot with two eyes open. I always shoot with two eyes open and it's the best way to do it, trust me. Always watch your pin on the target until your arrow makes impact and you'll never throw a shot.

The last thing you should try doing is this:

Try shooting at different targets. I don't know if you have some 3-D targets or anything like that, but it's a lot of fun to shoot at a couple different 3-D targets. Try it out and see if it helps!