yorec already mentioned this, but for as much as this technique helped ME, it bears repeating....
I was wobbly until I started using a "Push, Pull" technique with my Weaver stance. That is, with your gun hand, push out (employing the triceps), while with your support hand, pull in (employing the biceps). Use equal amounts of tension in both hands and they cancel each other out, leaving - for me at least - a much steadier, less wobbly sight picture. Give 'er a try!