Check out the official Newport Jazz Festival Web site (see Resources below). It includes a detailed list of musicians and a schedule.
Look at the performers and make a short list of those artists you cannot miss. Add to the list those artists you would like to see.
Take note of the acts that you have not heard of. Write them down and go to your friends or a music downloading program to sample some of their stuff.
Check the schedule on the Web site. Depending on when you check it (the festival is always in the spring), the schedule may not be finalized or even available.
Determine the artists you can and cannot see. Keep a list of your "must-see acts." This will help guide your scheduling.
Get your tickets early from the Newport Jazz Festival Web site. When you are running late, though, check Newport classifieds or eBay.
Arrange for accommodations. The Newport Jazz Festival is three days long, so if you want to go for the whole event, you will need a bed to rest in.
Arrange some kind of transportation. When you can get a hotel close to the festival grounds, you might consider flying in. You might not even have to use a car.