A couple of shooting specific exercises that help, in addition to the normal ones, are:
Hand strengthening ones using a soft squeezer ball.
Wrist strengthening ones winding and unwinding a light weight attached to a rod and string.
Pushing a weight out from chest height, holding it a few beats and pulling it back without letting it dip down.
It's never to late to start.
Lock the doors, they're coming in the windows.