Eat food and drink a stuffload of water.
NOS energy drink is also the highest caffeine content of any standard energy drink brand and half a can of that picked me up till past 4am when I had to write my game pitch document a couple days ago. Don't drink it all at once though. Have like an 8th of the can every 30 - 45 minutes, spread out by sipping it throughout. I tended to use teacups as the small size made it too difficult for me to drink quickly if I poured it each time.
