The first part of any good science fair project is to come up with an interesting and unique idea. They don't have to be groundbreaking or require expensive equipment. They can even involve things you have around your house. For example, one student in Indiana won her state science fair studying the development of drug resistance in bacteria in reaction to their exposure to anti-bacterial soap. There are lots of places to inspire you: science museums, books about scientists, and the internet are all great places to find food for thought. However, the most important part of any good science project is to ask questions about something you are interested in and then develop a hypothesis about what you expect to find.

The second part of any science project for a science fair is testing the question that you have asked. For that, you need to develop an experiment that will answer that question. Once you believe you have an experiment that will answer your question, go ahead and try it. See what results you get and whether your hypothesis was correct. The final step is to present that information at the science fair.