I have found this to be a great way to get over anxiety of calling a girls who's number you closed. I have mentioned this as a reponse in another post, but here is a more descriptive method.

The trick is before you get her number you make an agreement that you will call and she will answer, but not in a formal way. for example:

*this is just my close-method, you may have another*
Me: I need to go but I'm gonna be *insert event, place, or plan for later here* on *insert date*. I'll give you a call and see if you would like to join.
HB: But you dont have my number
Me: So?
HB: I can give it to you
Me: If you insists
*Close*

This accomplishes 2 things.

1st of all, you get around the anxiety of asking for her number point blank by hiding your intention behind a subtle invitation. Its not as forward but it accomplishes the goal.

2nd it creates an informal agreement. you will call her, and she knows when and for what. she will also answer when you call, because you told her who you are, and the reason for your call. its almost as though you were making plans with a friend (because infact you are).

by not creating this comfort upfront, it will lead to a higher level of anxiety when you call. best case scenario will be she answers (and unless you are super used to cold calling) you will be nervous, and be more likely to fuck it up.

Hope this helps you guys. Also feel free to add feedback.

after you start calling girls and getting used to talk to them on the phone it gets a lot easier. You are always going to think about that first call as you did the first approach, but just pick the phone up, hit call, and listen to it ring. I have found that most girls when you call can be nervous and will just talk and talk, so don't worry it is never just you.