As crdo8 said, distractions are one of the best methods of getting rid of your nausea. Read a book, draw a picture, do anything possible to focus your mind elsewheres. If you do attempt deep-breathing, you must take caution so you don't begin to hyperventilate (I have done this by accident many times).
Another method is something that was taught to me: Full body relaxation. The anxiety brought on by your nausea can simply make it worse, because it stresses out your body all the more. Find a small, quiet spot, close your eyes, and concentrate fully on your body, on loosening the muscles, starting from your toes and upwards.
I hope this helps. = 3