Well after you get your bow all tuned up, have the proper arrow spine, and you know shes shooting strait. If you still are having issues, focus on some of these tips:
Relax your bow hand. You want the bow to hold itself in the meaty portion between your thumb and pointer finger. You want the tension of the bow to keep it in your hand, not the grip of your fingers.
Shoot on the exhale.
No punching of the trigger, you want to slowly squeeze. Maybe look up the back tension release technique. (ill be honest I still have problems with my release. It's my biggest flaw right now.)
Don't rush. (my other issue.)
Stop shooting if you get frustrated, come back to it when you have had time to cool off.
I have found that I shoot my best when I am happy and relaxed. Keep in mind nobody is perfect, so there is no such thing as a perfect group. There will always be an arrow that doesn't go exactly where you plan. It took me awhile to realize this.
Shoot less arrows, but focus more on each one. Quality over quantity is actually pretty darn important.
For hunting, practice shooting in awkward positions, sitting, kneeling, squatting, uphill, downhill.
After you release, hold your bow up and your release arm up until the arrow has hit the target.
Shoot several days a week, to instill proper habits and muscle memory.
Most importantly enjoy shooting. Like I was saying, the moment it goes from enjoyable to frustrating its time to take a break.
Do all of these and you should see improvements in accuracy. I would say these are the most important basics to a good shot. There is plenty more on form, but if you can master all of these you will have absolutely no issues being deadly accurate to 40 yards. ( no guarantees though

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