If your feet are always cold and feel slightly numb and cramped from time to time, your circulation may need stepping up. Warm foot baths followed by cold ones often help.
When you are sitting down, make sure you do not cross your legs at the knees — this is definitely bad for the circulation. Instead, definitely cross your ankles occasionally.
If you are standing in one place for any length of time, try shifting your weight from one leg to the other every so often: standing still slows down circulation whereas moving the feet helps the pumping action of the leg muscles and heart:
One good exercise to do every evening when you come home is this: Sit on the edge of the bed on a sturdy chair and extend your feet so they are parallel with the floor. Lift them, one at a time, as high as you can… Then let both legs down. Repeat five times.