After each good practice shot, you should think back over the shot and visualize that good shot.
Then when you make the inevitable bad shot, immediatly visualize the good shot.
Once you have your form established, I don't think that you can learn anything from a bad shot. Try to put it out of your mind and focus only on your good shots.
This seems to be working for me. Every bad shot that I make is because I let something about my form slip. If I re-set by visualizing a good shot, it usually corrects the form flaw for the next shot. If not, I take a few minutes out, get closer to the target and focus on my form again.
The exception to this is if the bad shot is a result of equipment failure. Obviously, if that's the case, you have to stop and get it fixed.
Hope this helps,
Allen