I know your pain. I have a few breakthrus a few years ago. And got back on track. As you probably know, quanity does not add up to quality practice. I see some struggle, and notice they are snap shooting, and thier plucking thier release. I did that for 2 years. I finally got to shooting well for the last year.

I started getting to full draw. Holding for 2-4 seconds, until I was sure I was where I wanted to be,mental note that all wieght of the bow is on my back. And then consciencely, keep drawing back until you can relex that hand and after the shot, your release hand is a good 6" back.

I used to pull back slowly trying to hold on target, and it fly when it hit the corner of my mouth. I shot inconsistently, and bascially wasted my time practicing.

Another thing I did was move down a cheap 40lb recurve. I shot that for months, and then moved back up to my 52lb longbow, then to my 60lb recurve. I also shoot a 66lb longbow, and shoot it well for a few shots, but I know its too much for me. After 10 shots, old habits roll in. But the flip side of shooting the heavy longbow, is when I go back to my 52lb longbow, I feel I can hold it 30 seconds or more.