Besides shooting, how do you work on steadying? Dead holding a 5 lb. Weight in front of you? I would think steadying would increase after you are used to holding the weight out in front of you. Thinking of things I can do sitting on the couch at night etc.
An excellent book that made a profound positive impact on my marksmanship is "Sight Alignment, Trigger Control, and the Big Lie" by M/SGT Jim Owens.
In it, he discusses this (among other things) and how the USMC's rifle team trains for it.
If I recall correctly, one method involved "up's" where they held their rifle on target for a period of time. Then....after doing that for a while, they then had to do it some more--- with their boots tied together at the laces and draped over the barrel.
But...get the book. It's worth it. I gave my copy to someone, or I'd double check my memory on that. I need to buy myself another copy....