This is an interesting question because all you can hear on the phone is words and tone of voice. Perhaps you can hear what's going on in the background. But you can't hear what she's saying with her body or visa versa.
It's best not to talk to a girl on the phone for a long time if you haven't met her in person yet. Here's why.
Sometimes what we say without words is more important than the things we say. So the phone puts limits on how effectively we can send the right message.
On the phone we can easily turn her off talking about things that are a waste of time. But when you go out on a date, what you say isn't as important as long as she knows you like her.
Have you ever spoken to someone on the phone and then met them for the first time in person later? I bet it was a totally different experience.
That's why it's always best to meet a girl in person first before you spend hours talking with her on the phone.
Also if you've seen the way she is in real life, you're more likely to know what you can or can't say on the phone.
Basically on the phone you're running blind. Your conversation might be great. Suddenly you say something. She takes it the wrong way, get's turned off, and hangs up on you. It can happen.
But in person she can hear what you're saying and watch you at the same time. It's impossible to hang up and if she tries to leave you can easily explain what you really meant.
If the girl you're speaking with lives in the same town the best thing you can talk about is meeting in person. Sure, you can do a little small talk first just to break the ice. But don't waste your time.
Your number one goal before you start talking with a girl on the phone is getting a commitment for a first date.
If you've already been out with her, you should be calling to set up another date!
Caution. If you haven't met this girl before, don't wait more than a few minutes to start talking about meeting for a brief date, something simple like coffee or lunch or breakfast, ...
You don't want to tell a girl you have all day or the entire evening or an afternoon, because if you meet her and she's not what you're looking for it's going to be a very long date.
Sometimes it's easy to have such a wonderful, magical conversation that you forget to ask her out. The longer you wait, the more awkward it becomes, plus you risk that she might suddenly need to get off the phone. It's best to make arrangements to meet ASAP.
Don't waste time when it comes to asking her out on a date. After that's out of the way you can continue your conversation if you want.
What I recommend is to get off the phone shortly after you've made your plans to meet. That way you don't risk saying something that will turn her off. Explain that you have another appointment but can't wait to see her.
Girls like busy guys who have a life and things to do. You will impress her if you get to the point in a reasonable time. The fact that your busy and hard to get is a turn on as well. Most girls don't like 'needy' and whimpy men.