The following will determine your energy level:
0) Thoughts. Have happy thoughts. Do this by doing happy things. Play with yourself - no not that kind of playing - and associate yourself among others who are happy. Simply being around people who are happy can make you happy thus making you have energy boost.
1) Fluid. Water does the body wonder. Drinking soda, coffee, etc are no subsistute for water. Drink water often, and drink plenty of water.
2) Exercise. Just moving around helps. Take a walk or something. You can also try weight lifting, running, swimming, etc.
3) Diet. Eating poor things like chips, snacks, fast food, etc are not good eating habits. Eat whole food all day, and try to limit or restrict fast food and candies. Eating fruits and veggies will really help with energy level.
4) Sleep. No amount of exercise, diet, or fluid can replace a good sleep. Sleeping should be at least 8 hours, but for some it can take 10-12 hours before they're fully rested. Per week, you should spend somewhere around 84-112 hours up. The rest should be spent sleeping.