Welcome aboard, emma.
The most popular way is to create convective air movement. Most people find blowing on it uninteresting, so they use their warm hands to create air currents instead.
A second way, I have heard, is with static electricity. Some people think that that works better with aluminum foil pin wheels. I haven't tried that one myself, but here are some plans and instructions for a foil wheel:
http://www.flickr.com/photos/13660011@N08/...57602065042568/