Re: Tips for off hand shots, PLS.
try silhouette shooting / competition, either highpower or smallbore (rimfire).
http://www.riflesilhouette.com/
http://www.zediker.com/articles/zcomlawt.pdf
similiar searches concerning silhouette will give you a whole bunch of tips on your frame, breathing, trigger control, follow through, grip, etc.
combine that with sling use tutorials and with practice you'll have a winning combination.
for me, (without a sling) starting square to the target (like teeing up in golfing), then moving my rear leg more toward my six, raising the muzzle of the rifle up and letting the butt lock into my shoulder, elbow out, dropping the reticle onto the target, slight cant to the rifle actually using the chest for some support, locking my forward gripping elbow to my side / hip and leaning back just a tad seems to work (although recoil management sucks while leaning back). i also have found (for me) that using my forward gripping hand webbing between my index and thumb pushing rearward against the trigger guard works well to "lock" my upper body into place, and aids with pushing the butt into my shoulder. it's just is more comfortable for me.
pivot at the hips, don't try to raise the rifle with the arms, you'll fatigue quicker.
i also like to concentrate more on the reticle than the target, for me it helps the mind games with the wobble. breathing in and releasing, when the color of the target is behind the crosshairs at the bottom of releasing the breath, i squeeze.
i've been tinkering with using the tip of my finger against the tip of the trigger and dragging the bottom of the trigger guard with the bottom of the finger. seems to be working.
i also tend to pull up on my off hand shots, so either i aim just below the intended POI, or adust a little lower on the turret.
that's what works for me, but maybe not for anyone else.
greg's input is golden.