Do not listen to music when running - Do not wear headphones when running outdoors. The music may motivate you but you are in danger of missing the warning sounds that will keep you safe.
Do not lean back while you run down a hill - When running downhill in order to gain speed, yet maintain control, lean slightly forward at the pelvis. In this position the gravity will give you speed but you will also alleviate some of the pressure on your heels. If you try to stop yourself by slowing down, you will use more effort. If you are in competition, you will benefit by not exhausting yourself in trying to reach the top of the hill, because you will have that extra energy to actually run and not "fall" down the hill.
Do not stop when you run uphill - During your workout, resist the temptation to stop running and walk up an incline. Walking up a hill takes more effort than to keep running at a slower pace. Reduce your speed to small, light steps. Keep your breathing at a calm and regular flow, and your upper body movements in sync with your pace. If you stop and walk up a hill, the gravity will make your body seem heavier and thus force you to proceed with a higher expenditure of energy.
Do not run in place - Correct movements are the key to safe and fast running. Work on your running tecnique. Avoid running "on the place" jumping up and down, instead try to go forward. Make sure your feet do not hit the ground flat, slapping the course. Use the swing of your arms to help you go forward.