[Xero]

Since your problem seems to be confidence, one way is to get used to being rejected. You can accomplish that by asking any random girl that is way out of your league and that would work. Another way is to talk to your self in a mirror and repeat it a thousand times. I don't really know if this is an option for you, but you can go to they gym and lift some weights. That builds confidence due to the chemicals in your brain increasing.

How long are you talking to these girls, just once, a few times, or a lot. If it's once you can ask for their number, just be ready for a no. You can reply "ok your loss" and walk away. If you have been talking a few times the phone number would come a lot easier. If it's been a lot and you still cannot get their number or are afraid to you can drop them a note.

I think asking for their number would be best, you can continue to talk to them more, and you can then ask them out later. Asking for their number gives them an idea that your interested and they wont be blown away from a random "will you go out with me".

If you have any further questions or want to go into details submit another reply on this thread.

Hope this helps.