Grab one hand with the other and gently squeeze. The working hand is positioned around the targeted hand. I like to wrapped my working hand around the knuckle level and then move up and down the hand.
When you squeeze you may feel some pain. Back off a bit and reapply. Reposition your working hand and start squeezing again. Always work within your comfort zone and use sense when working with injury or arthritis.
I feel like I am "working the kinks out" when I do this. And I love to go up into the fingers. Do it everyday and even several times a day if you use your hands a lot.
After awhile the pain fades away and your hands will feel a lot more flexible. Because the hand helps set the tension level for the rest of the body it helps you relax overall.