Before you start drinking, give your car keys to someone who won't be hanging out with you. If you give them to someone who is hanging out with you, chances are after getting drunk you'll be able to convince them to give you your keys.
Carry an ink marker with you when you go out drinking. For every drink - put one mark on your hand, so you can assess how much you consumed the next day.
Bring a house warming gift
Housewarming gifts are a great way to show your appreciation for your host and make a good first impression.