Dress for the occasion. You would not believe how many times over the years I've seen people, on the ice, not dressed warm enough. This is, after all, winter in Wisconsin. When you are cold, not only will you not enjoy the sport, the cold will affect your thought process. It's easier to make bad decisions.
Bad decisions can lead to accidents.
Get yourself a decent helmet. The 4LIYC requires a helmet for racing, but even if you are not racing a good helmet is a safety must. Notice how many of the serious racers use the full-face style helmets. Be sure to have ice creepers on your boots or some type of spiked shoe. It makes walking on the ice safer and they are necessary for starting your boat.