First and foremost, when you plan a party, put yourself in the mind of a non-drinker, and make sure that even if your guests don't want to drink, they can still have fun. Make sure there is food available.
Food causes alcohol to be digested slower, which is good.
Don't mix alcohol with drugs. Both legal and illegal drugs may interact with alcohol. Be careful not to take even aspirin before, shortly after, or while drinking. Mixing alcohol with carbonated beverages increases the speed that the body consumes alcohol. Have non-alcoholic drinks available.