One of the most important aspects of tailgating is to drink responsibly. Often times you'll see people come to tailgates unprepared and just grab a beer or take a shot and the rest of the day becomes a blur. With a little preparation, you can ensure you have a great time and are able to sober up before it's time to drive home after the game.
Alcohol and food are synonymous with tailgating, and consuming them in the right order (and amount) goes a long way to determining how you feel, and how long you feel, the effects of the tailgate.