Write an article based on this "Use the phone number sparingly once you have it."
You don't want to end up in the situation where he so regrets that you got hold of his number that he goes and changes it just to be rid of your texting and calls! The phone number is just a small step in growing your relationship, so spend a lot of time on all the other important aspects, such as getting to know him face-to-face and hanging out together. Use the phone as a tool to make meet-ups, not an excuse to pour out your heart. Don't text him too much. Good job if you get his number, but don't annoy him and make him regret his decision. Be mature with what you say, and have fun!