I had the same general issue. About year into the RSD, my left hand just stopped working and contracted, so I was unable to use that hand. Thankfully, I was right-handed, so I still had my "dominant" hand working for me. It finally started twitching after about two years, so me and a PT worked from there. I still have some weakness in it from not being able to use it for so long and the subsequent atrophy, but it's been working for about three years now.

Back to the question, in order to get things done with one hand, I became quite creative if you will. I put an ace wrap in order to uncontract my hand and prevent it from permanently staying in a tight fist and to keep my nails from digging into my skin. It was softer than a brace, so it helped with comfort. It also made people cautious about bumping into my hand and such. This also helped with being able to use my useless hand as a kind-of hand. I just practiced the little things at home and, as odd as it sounds, tried to make a game out of trying to do things with my one hand. It helped with the outlook a little bit...if I didn't make it into a game, I would focus on how I only have one functioning hand, and that wouldn't make things any better. I learned to use my contracted hand's wrist as support for things that needed two hands. For example, when putting my hair into a ponytail, I would push my non-functioning hand into and out of the scrunchie in order to put my hair up. I also learned ways to get around having to need a second hand. For example, usually when folding clothes and blankets, people just hold them and fold. I adapted and used the floor to fold. I would lay the clothing/blankets/towels/etc. and simply fold that way. With tying shoes, I'd tie them before putting them on and use my teeth or foot as my left hand. Also, I used duct tape to tie them. I'd put a piece of duct tape at the end of each lace. When I needed the second hand to hold/secure a lace, I'd tape it to the floor and simply do that each time I looped and such. I was - and still am - very independent, so I didn't want others to help me unless it was absolutely necessary (i.e. carrying groceries). I was also on crutches at the time, so there were some things I already faced that I was unable to do and had to rely on others for (i.e. pushing a shopping cart), but I just used creativity in order to get around my lack of a functioning hand. The best I can say is keep as positive of an outlook as you can and get creative with your other functioning limbs as well as outside resources - like duct tape - in order to keep as much independence with completing tasks as you can.

I hope this helps!