Try non-caffeinated drinks on a shoot morning. Switching to decaf coffee bought me 2-3 points per shoot, but on non-shoot days I normally drink a *lot* of coffee!
Also optimise your position so you're using the absolute minimum muscle power to maintain a steady aim = "natural point of aim". A trick is to get on target then close your eyes and consciously relax for a few seconds, then open your eyes again and see where you're aiming.
I find supported standers/kneelers too unstable laterally, and 4 times out of 5 will shoot better unsupported as I've got more control of the position.