1. Drink adequate amounts of water. This is especially important if sports are played, or vigorous exercise, and now that it is summer and done outdoors, makes this even more critical. Sweating causes a loss of fluid and electrolytes that may cause the muscles to spasm. Staying hydrated before, during, and after is the best advice. It does not matter if it is cold or warm, just get it down.
2. Stretching exercises done before bed can be beneficial if you are prone to night cramps in the calves. One of the best exercises to stand about two feet away from a wall. Place each forearm against the wall, and keep a straight back. Feet need to be flat on the floor, and hold the stretch. It is best to do this before any symptoms start. Another one can be done while sitting, to hold both feet out in front of and flex each ankle. Repeat this several times. If sleep is disturbed, the best option is to get up and walk around until everything calm down, then return to bed.
3. Eat a well balanced diet, and take a multivitamin. If you regularly eat proper portions of protein, complex carbohydrates, fruits, vegetables, and dairy, you should be able to get all the vitamins and minerals the body needs to work normally. The regular runs to the fast food restaurants or consuming other preservative filled or sugar coated things cause a disruption in proper function. Try and avoid the temptations.