What should I know about riding roller coasters?

I'm going to Hershey Park tomorrow and I've never ridden a roller coaster because my family never really goes to amusement parks. I'm going with all my friends so I know they'll want to go on the coasters. I was watching some videos and they didn't look to bad besides Sidewinder and Fahrenheit. I just don't like steep drops like Fahrenheit. I want to go on Storm Runner though. What can I do to help that "stomach dropping" feeling? Or anything else I should know?