warm up properly and slowly, no rushing into it. You get a stich wenn your diaphram (helps you to breath) doesn't get enough oxygen to work properly. So you have to warm up slowly and properly to get your blood circulating.
oh right-i think i might have misunderstood your question-do u mean a medical stich that closes a wound? coz i thought u meant the stich you get on your waist that hurts whilst running real fast without getting warmed up properly.