First of all, men like to do the pursuing. If you start pursuing him, you take the opportunity and the fun of it away from him, so don’t go asking him out yourself. He’ll feel that you’re so much more a prize if he has to pursue you, does, and wins your attentions as a result. Guys love to win!
Second, sometimes men need a little reassurance. You can give him the reassurance without taking away his manly duty to do the asking out by turning up the heat on your flirting with him. Don’t throw yourself at him, but do send him signals that are non-verbal. For instance, you can do a lot with your eyes that show him you’re interested without winking. Hold his gaze. Don’t look away. If you catch him looking at you when he thinks you’re not, give him a winning smile with a little bit of an “I know what you’re thinking” sparkle in it.
Men love it when you laugh at their jokes, and listen to their tales of “slaying the dragons” at the end of the day. Practice doing this. Even if it’s a mercy giggle, be generous.
Compliments are wonderful free gifts. Tell him you think he looks really great today. His hair is so much sexier than it used to be three years ago — that kind of thing. After doing all that, he’ll get the message from you that you’re interested, without your seeming easy.
If you’ve given him something to chase, and he’s not chasing, then it’s time to move on and understand that although you like him, he’s not moving at your speed, or he’s not interested in you as more than a friend.