Also one thing that I feel is important that has not been mentioned yet; don't forget breath control. If you take nice deep and calm breaths you'll notice that all the shakes from adrenalin are gone, and then learn to shoot on the exhale (or inhale, whatever feels better to you) as that creates a more stable shooting platform than breathing at shot.

Got the Bowhunter magazine that Bowwalker is talking about, and I'd recommend it, it's got a few good reads in it.

If you are not waiting till the pin hits the X until you fire, what do you focus on?
He points out that you should squeeze the trigger slowly while the pin floats in the general area of the X to avoid punching the trigger. I found this way applied to finger shooting is optimal for me, as the pins float over the target my reflexes allow my hand to relax before the pins are perfectly aligned over the X, and most of the time it gets me into a good group near center. This is the only way I've found to consistently hit bulls eye, as releasing on the bulls eye always means a miss for me, but releasing instinctivly before the X is a better chance of hitting dead center.

The best thing that article finishes with, is whatever your preferred method, do it consistently. Consistency is key.

I'm curious, I see your bow is 70#. Now obviously you can draw it comfortably, that's not what I'm about to ask. However have you tried dialing your bow down to 60# (I'm assuming that 70# is your peak and it can go down to 60#)? You may find that you have greater control, less shakes, and a easier time bringing the pins up to meet the target area with a lesser draw.