I had a stroke which left me totally paralyzed on the right side. Since my dominant hand was right-handed, I lost function to write. I was taught to use my left hand. However, some good news for you. After 6 1/2 years, I now walk with a cane, and use my right hand for everything now, except writing. I think that will come by the end of this year. By the way, I've been driving now for 3 years. The exercises do work, I can personnally attest to them.
Here are some exercises that will help:
1. Take your arm, and with the other hand massage the affected arm, trying to loosen the muscles. If you keep doing this, eventually it will loosen up. In rehab this method is called “Miofacial Release”. The therapist did for me and I continued to do it at home. It really worked on me. Ask at Rehab if they offer it.
2. Stengthen your whole arm including your fingers, by taking a plastic grocery bag and put a few groceries, adding more and more weight when you think you can. You'll be surprised, by carrying the bag with 2 or 3 fingers, you'll see how strong both the fingers and arm become and the muscles will loosen up.
3. With the affected hand, pull the fingers on the opposite hand, one at a time, and keep stretching them out. Stretch each joint on the finger, the 3 joints on every finger. I constantly did this. My hand used to be like a claw. You should see it now. I am even touch typing this note using every finger on both hands. It takes a strong will, perseverance and a lot of work.
Take the good hand and pull on the thumb stetching it, farther and farther from the index finger. After a while, you'll notice you can separate the thumb from the index finger until it is normal like your good hand.
4. Then when you have accomplished this, just try opening and closing the fingers, over and over until they become strong.
5. Use a tight springed clothes pin, and keep pressing it open, this will also give strength to the fingers.
6. Put some small type shaped pasta or marbles in a bowl and try picking one at a time up. This gives coordination.
Hope this helps!