Both are stressful, intense minefields of potential gaffes. You're trying out for a position for which you feel grossly under qualified and someone with way better credentials than yours is always waiting in the wings. You're often unprepared and you are, quite likely, hungover.
Both come with some basic guidelines. You don't want to look like you got dressed in the dark. You want to ask questions and nod at the appropriate times. You want to appear interested but not too interested. And it's important to have a good resume.
Not on paper, necessarily, but in your head. When on dates, people look for certain qualifications. Here are six things that you should have on your dating resume:
Charity work. This demonstrates selflessness, and an ability to not think about yourself 24/7. Perhaps you've been a Big Brother or Sister, or run for breast cancer, or served food at a soup kitchen at Christmas. If so, it's always good to casually -- and subtly -- drop this into conversation. If you can't think of anything remotely charitable in your past, then you can say you've been seriously considering one of the above options (don't tell them that just thinking about it made you feel so good you decided not to bother). And, who knows? You might even inspire yourself to actually do something charitable. The Big Brother/Sister is a good one -- the time requirement is minimal (a few hours a week) and you might make a new friend. (And where there's a kid in need of a Big Brother or Sister, there's often a single parent.)
Friends with your exes. Exes make the best references, especially if they haven't taken legal action against you. (And if they have, well, it was a case of mistaken identity and anyway, your date doesn't need to know about any of that). Try to drop in the name of an ex or two and mention that you're still buddies. This can be tricky, though, because if you go on at length about your ex, your date might wonder if you still aren't carrying a torch. So don't tell him or her about the long weekend away that the two of you have also planned. But, it mightn't hurt to gently imply that you think the ex might still have a teeny thing for you, particularly if you're a man, as women are scientifically proven to be attracted to the things others want. Bonus points if you're friends with an ex-fiancé: this shows that at some point, someone liked you enough to consider spending the rest of his or her life with you.
Social skills. Having a group of friends demonstrates that you are capable of human interaction and not some kind of cave-dwelling troglodyte stuck in a World of Warcraft. And the more friends you have -- real friends, meaning people who actually know you, not names you've collected on Facebook -- the more likeable you appear to be. A mixture of both same and opposite sex pals suggests that you are well rounded while having only opposite sex friends suggests you're an eternal flirt and perhaps competitive with your own, and having only same sex friends suggests an inability to relate to the "other." Talk warmly about the people you know and say nice things about them. Liking others makes you likeable.