Give your man space. Do not expect to spend all day, every day with him. While you may spend a lot of time together in the beginning, there usually comes a time when the relationship cools off. Don't fret. This doesn't mean that he has lost interest. Try to plan time together once a week and let him go out with his friends as much as he wants.
Do not call a million times every day. Any man who feels smothered is going to jump ship quick. Once a day is fine, maybe to say good night.
Don't start telling him "I love you" early in the relationship. Even if you are feeling that way, it may scare him off. Don't try to force him to say it either.
Don't feel suspicious if your man doesn't open up right away. Men are more likely to talk about what they've done instead of how they feel. Just because he isn't ready to tell you his whole life story doesn't mean he's hiding something.
Don't expect to move in together a week after you start dating. Men are generally very slow movers. Give yourself at least a year.
Let your man know he's appreciated. Let him know how much you enjoy spending time with him. Contrary to popular belief, men are not mind readers. Don't expect them to know what you are thinking all the time.