It just depends. If it is regular, go into the bathroom, and breathe deeply, and try to lower your blood pressure by calming down. The slower your heart beats, the slower your blood will fall out of your nose. If it goes on for about an hour, I suggest flushing the toilet, and then hanging your head over it. I have been told many times that you should NEVER put up your head and try to keep the blood in your body. You will feel dizzy, vomit, and pass out, and probably break your nose, thus worsening (don't know if that's a word or not) the problem.
I have nosebleeds regularly in the summer, but it turned out to be an infection. Now they have stopped, but it's winter, and nearly 0 degrees.
If they keep coming, go to your doctor, and they will figure out the problem. The last thing someone needs is a severe problem because they keep having nosebleeds.