It's true that a daily dose of booze can do a body good. But alcohol, of course, is a poison as well as a tonic, and after one serving (12 ounces of beer, 5 ounces of wine, or 1.5 ounces of hard liquor), the cons can start to outweigh the pros. Drinking is linked to a number of cancers, as well as heart and liver damage.
Sip on your second- or third-choice beverage rather than your absolute favorite. This will make it easier to cut yourself off after one. If you're drinking wine, use a glass meant for white—they're usually smaller and can help you avoid overpouring.