If you're meeting a potential hookup out at a bar or restaurant, always keep an eye on any drink you order, and don't accept a drink that you didn't see the bartender prepare and hand to you. You should maintain this same awareness even if go to someone's house or apartment to hook up. Watch your drink being made closely so that you know exactly what's in it and can be sure nothing suspicious was slipped in. Resources like Undercover Colors can also help you test your drinks for drug tampering.