The number one rule: NEVER DRINK ON AN EMPTY STOMACH. I have done this so many times. And I've seen people recommending others to do this. It seems like a great idea, right? Save your calories for the day so you can get drunk with your friends. No. You will get drunk way too fast. You'll be the super sloppy drunk that no one likes. You will probably throw up, and you will run out of stuff to throw up and it will hurt. You have a higher chance of blacking out and that never ends well. But, most importantly, you will do major damage to your body. The alcohol will not be absorbed into any food. Your body will digest it faster and there will be very high concentrations in you liver. After awhile this can lead to permanent liver damage. So, before you drink, please please please eat something.
Never feel pressured to drink. Not drinking alcohol is the best way to avoid liquid calories. Just drink diet soda all night or even make up a mock-tail. If people are pressuring you to drink, then those people suck. You don't need to drink to have fun.
Dance! This is the best way to avoid feeling the guilt of "I ate a meal and I'm drinking." I love dancing at parties. It's fun. You meet new people. And it burns calories! No more guilt about have a drink! The best part it that if you embarrass yourself, just play it off like you're really drunk.
Have fun and be Safe. Parties are meant for people to have fun at, so enjoy yourself. But, remember to be safe. Use the buddy system. Keep track of how much you're drinking. Drink water in between drinks. Have safe way home (taxi, designated driver, walking). If you feel unsafe, don't be afraid to leave with your friends or ask someone to get you, even if it's your mom!