I have a lot of hand issues, though I still have use of both hands. If you have any grip, you can use anything from a stylus to a large knitting needle to guide fabric -- otherwise you may be able to rig a small harness to hold the guide. Get a machine that has needle up and a thread cutter. I use a needle threader all the time -- some machines have them built in. I have a guide that helps me sew a straight seam but I used to stack sticky notes on the side to get the 1/4" seam. For rotary cutting I use my left forearm to hold the ruler on the fabric and cut with the rotary cutter in my right hand. I have the June Tailor cut 'n shapes and can keep it stable with the palm of my hand or my forearm (when my left hand hurts too much to use the palm). I use a lot of pre-wound bobbins since they save my hands. DS got me one of those rulers with the cutter attached and I find I am able to keep it stable without major issues. It took me a lot of practice to develop the techniques I use, and when I went to classes I have to educate the teachers to accept the way I do things and not continually try to correct my cutting techniques. Just don't give up -- there is always a way.