Pick a bar in a safe neighborhood if you're going to drink with strangers. You are less likely to be preyed upon in a safer, more populated environment. Consider bar-hopping until you find a bar that meets this standard.
Buy your own drinks. Don't ever let anyone else purchase a drink for you unless you're at the bar where you can see it being made. It is possible, especially at nightclubs, for your friendly drinking buddy to slip a drug into your drink to tear down your defenses.
Take your drink wherever you go. If you let your drink out of your sight around strangers, it is possible something bad could happen to it. If you can't take your drink into the bathroom, finish it before you go inside.
Limit what you drink. Getting drunk around others is okay when you're with friends, but strangers have no obligation to make sure you get home safely. Consider just ordering one beer, and stay away from shots.
Go home alone. You might meet an appealing woman while you're out, but your judgment may be impaired because of the alcohol. Remember that you don't know this person, and it is entirely possible that you will wake up the next morning and find that your wallet is missing--or worse.