The more you interact positively with someone, the more they'll like you, says David Lieberman, an expert in human behavior. And several studies back him up -- showing repeated exposure to practically any stimulus makes us like it more (as long as our initial reaction wasn't negative). So forget about being aloof, evasive and unavailable in the beginning. Instead, find excuses to spend time with him. Now, pay attention, because this is the tricky part. Just when you're convinced you've won him over and he likes you, start being a little less available. And then even less, until he hardly sees you at all. You've now effectively instigated the "law of scarcity." We all know this one: People want what they can't have. By constantly being available, you diminish your value. If every time you walked outside your front door there was a huge pile of diamonds to step over, you'd hardly see them as precious would you? Be around and then not around for awhile and you'll give him time to think about how much he likes and wants you.