Never drive or take part in other risky behaviour while or after drinking. Don't drink alone. Only time will help. Giving coffee or other forms of caffeine to someone who's drunk only results in a livelier drunk. A cold shower just results in a wet, cold drunk.
Nothing works except time.
Make conscious choices about drinking. When you do decide to drink, remember that each situation is different and there may be several factors to consider. I'll plan in advance for a safe way to get home. I won't drive if I've had anything to drink and I won't ride with a driver who has been drinking. I won't play drinking games.