Aha, number one on the Bristol Stool Chart....
http://en.wikipedia.org/wiki/Bristol_Stool_Scale.
(Believe it or not, the academics have made a science out of szh!te)
Try and eat as much fibre as possible, at every oppurtunity- up to 5 -portions a day, orange juice with the bits in, fresh fruit, loads of veg, and don't neglect the fluids either.
If your bowel habit has changed, consult a doc.