Tex,
One thing that helped me get better was to video myself shooting and then analyze my own form. I think I finally got a form that I like and can easily repeat. When I do it correctly I am pretty damn accurate. When I deviate, i am all over the place. I have found five things that seem to really effect my shots. All five things change the flight of your arrow. Once each thing is consistent, your arrow will fly the same every shot and then you can actually learn to aim.
In order of appearance in my shot cycle they are...
1- Grip... Gripping the bow in my left hand the same way everytime. This helps give the bow the same vibration and movement on release. This seems to have the smallest effect out of the five, for me anyway.
2- bow lean... Consistently leaning my top limb the same degree to the right. I try to match the lean in my draw hand to prevent string twist, which causes all kinds of crazy flight. (Cork screw, fishtail or porpoising) The lean changes the way the arrow jumps off of the bow. For me, too verticle causes shots to go left. Too much lean and they go high.
3- Drawlength... Drawing too short causes lower velocities and can cause low shots. It also causes the arrows to act as if they are too stiff for the bow, because they flex less when not fired from full draw. Whatever your length is, you should draw to it everytime and then shoot correctly spined arrows for that length. Every inch of draw short can be a decrease in draw weight by 2.5 pounds.
4-anchor point... This one is obvious. You are your rear sight. You need to draw to the same point everytime or it is like shooting a rifle with a wobbly rear sight. I shoot 3 under and draw my middle finger to the corner of my mouth. My thumb rests right on my cheek
5- release and follow through... Everyone knows this but many still F it up. Instead of consiously opening my hand by pointing fingers, flicking them open or just relaxing my grip, I just think "anchor point, aim, touch my ear". I put my pointer, middle and ring finger flat on my ear with my middle finger over my ear hole. It seems odd but this makes me not actually consciously release the arrow. It just happens. This prevents me from pulling the string away from my face right before the shot.
When I do these 5 things the same way, I shoot rediculous groups and can hit whatever I look at out to about 25 yards. When I miss it is usually a combination of one or more of these things. You can do any of these however you want, just do them the same way every time, no matter how unorthodox your style, you will shoot well if it is consistent.
There is a ton of other stuff that goes into archery, but it is usually "the indian, not the arrow".
