As a new pilot I caught a C172 on fire once. Scared the *rap out of me. It was hard starting, I made the critical error of getting too much fuel in the induction system. Did this by pumping the throttle in my failed gyrations while cranking. I put it out right quick with the fire extinquisher, no damage done. Had the A&P come out and look it over.
Since this event I've had a keen interest on the right thing to do, as I had already figured out the wrong thing. One bit of advice I have been given, which seems to work for me, is to prime the engine before you start the preflight walkaround. Fuel puddled anywhere won't burn. Fuel in vapor will. When it is cold give the fuel more time to become vapor before you crank the engine. This seems to work for me.
-- IFMU