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. In spite of our best efforts, injuries do occasionally occur. My advice then is ice, ice, ice for 2 days. Then ice and hot treatments for a few days. Also increase your vitamin C intake and try to find the cause of the problem.