Meditation is great. You can start with deep breathing and sit down in a comfortable position and repeat a mantra or a work over and over. Your mind will feel cleared of distraction thoughts and your body will relax. It helps to close your eyes too.
A Number Of Things. Several ways to calm yourself: take a walk or a bike ride, spend time with a loved one, read the newspaper or a book, eat a healthy meal, do something nice for someone else, go for a swim, take an aerobics class, volunteer at your local community center. If none of these ideas helps to calm you down, see your primary care physician and discuss your nervousness in more detail.