Make sure you are doing your pelvic rocks (the hands and knees position that someone else suggested, where you first arch your back toward the ceiling, and then toward the floor). Also, use good posture whenever you can. Sitting straight, crosslegged is best, or on a birth ball. When you are sleeping, make sure you sleep on your side and have a pillow between your knees to maintain good pelvic alignment.
Hope these suggestions help, I'm sure there are some other women out there who have even more suggestions!