If you’re shopping for long-term love, research suggests you start the narrowing process before you even go on a first date by looking at occupation. Why? A person’s career choice is a statistical indicator of their long-term relationship potential. Strictly by the numbers, you should look for an optometrist, a nuclear engineer, or a farmer, as they have the best chances of marital longevity. As for occupations to avoid? In a 2010 census study of divorce rates by profession, dancers (43 percent), bartenders (38 percent), and massage therapists (38 percent) scored devastatingly high.

When you finally meet face to face with that optometrist, how long do you have to make a good first impression? Five minutes? An hour? Long enough to at least order dessert? Nope. It only takes a tenth of a second to form a first impression, say Princeton researchers. And it doesn’t matter how funny your jokes are or whether or not you offer to pay for dinner. Longer exposure can’t alter how your date saw you when they first cast their (no doubt impeccably bespectacled) eyes in your direction.

To get a sense of whether or not you’re off to a good start, use some good listening skills. No, no, I don’t mean you have to listen to what your date says. This is more about how they sound when they say it. Researchers say voice modulation matters. If your date’s voice is animated, rising and falling during the conversation, that’s a sign that they’re attracted to you. This is especially true for women.