I also have hand tremors but maybe not as bad as you do. I find to thread a needle, I loop it and push the loop thru the needle eye. Seems easier than trying to push the end which may or maybe not be frayed. As for sewing on the machine I use feet with a side flange to help me keep it even. I also keep my eye on the fabric at the needle as much as possible as that's where it could go off on you or at least it does for me. I have robotics on my quilt machine as I know my hands will jerk at the wrong time.