I tend to agree with TM and 500WE. Practice different positions. When on the ground still hunting, you never know where that deer will show or turn up. Practice in at least two positions, i.e. brace your hands or forearms against a tree (not the gun - see bark blast above :))with a two hand hold, try using the non-strong side arm against your chest as a brace.

When in a tree stand with a rail, I place a 1x4" board across the rail and use a small sand bag to sink the .44 Ruger trigger guard into. This will allow you to shoot left, right, straight ahead, up or down. It's been very successful for me. Hope that helps, and good luck.