Acknowledge the fear. You may hold a fear of roller coasters so deep that you've never really taken a moment to reason with yourself by talking it out. Even if you're only talking to yourself, verbally speak the things that scare you about coasters. Get it out of your system as a means of "releasing" the tension that is preventing you from experiencing the fun that roller coasters can provide.
Do the math. According to the most recent data provided by the International Association of Amusement Parks and Attractions, close to 300 million people rode amusement rides in the United States in 2007. Based on government-regulated statistics, the chances of being fatally injured on an amusement park ride is one in 750 million.
Open your eyes. Although it is natural to think that you should close your eyes to scary things, you may find that keeping your eyes open during the ride will help you get through it with less fear, because you can see what's next. When you know what to expect, your brain can better prepare your body and heart for the next phase.