Hmm. only tip i know is massage ur temples (hollow parts ontop of your ears) it is where ur sinuses go and the blood flows thrue there to your nose, if you massage with some pressure you will stop the bloodflow to your nose thus stopping the bleeding
Chances are the lining of your nose is very thin, or you have high blood pressure. Your Kiesselbach's plexus might be inflammed. (That's the divider part of your nose, near the front.) I read on webmd that it can be a sign of cancer also. X_X But I don't think you have cancer.