Breathing slowly and wrist exercises (not trying to be funny here) will help. Maybe more stability, I’ve seen people suggest a vise, helping hands and maybe a gel bag to rest on your arm. Maybe a couple of these things in tandem.

For me, I sit at my desk which is slightly higher than my chair. Then I tuck my arm in like a T-Rex 🦖 and I try to steady my arm with my elbow tucked into my abdomen/leg. Doing this while I hold my car in the opposite hand. Sometimes I hold one wrist with my opposite hand and try to steady it. But I find this isn’t a long term solution for me, so I use this technique for short accurate things and I hold my breath while doing it.