I was also told that every now and then if you stop mid-wee and hold for a few seconds, it can help.
We also did some exercises where we sat on our knees with our arms on a chair. We had to tilt our pelvis up and down whilst holding the muscles. It was all rather involved (and would have looked rather interesting from behind!). We also did some other exercises sitting on the edge of a chair and tilting our pelvis. I have to admit, I haven't done any of those since!