Going from your first phone call with a woman to your first date is a big step.
The first phone call with someone you met dating online is your first "real" interaction with them. Fortunately the process of going from the phone to an in-person meeting is easier and faster than messaging back and forth.
Also, because of this, I think it’s important to point out that just because the first phone conversation doesn’t seem to go well doesn’t mean that you shouldn’t meet the person.
Again, for me, preparing for the first phone call isn’t about preparing for the call.
I don’t see moving to phone calls as a bad thing, but I found meeting in person was much more valuable and more revealing so I aimed to get to the meeting part as quickly as I could.
I found that detecting chemistry over the phone wasn’t something I was good at.
You have officially gone beyond cyber space and have exchanged private contact information. You should be using this initial phone call to get to know the woman you are talking to and make sure they are worth the time and effort to meet in person.