Carbonation increases the rate of absorption of alcohol into the bloodstream. Mix your own drinks , so you know what's in them. Caffeine or cold showers don't work. They make you more alert, but don't affect how your body metabolizes alcohol. Once alcohol is in your system, the rate of metabolism is constant.
Alternate alcohol beverages with noncarbonated, non-alcohol beverages, such as juice.
Some combinations can be deadly. Avoid punches unless you're clairvoyant and can predict how much alcohol is in the punch. Vomiting doesn't work. Unless it occurs immediately after drinking, most of the alcohol will already be in your blood. Besides, it's not that attractive or fun.