Do not eat before running. I always feel run down and often have stomach aches if I eat up to 4 hours before the run. Adjust to the weather. Wear layers when it is cold. Drink Water on hot days.
Water is a great cooling agent.
Remember the hardest part of a run is getting started. Look forward to the workout. Staying injury free is always the best policy. Common sense is a big help. Do not run hard every day, alternate your workouts, wear good shoes, stretch, run on soft surfaces, listen to your body, and eat well.