Before the call
Write down the key dates, the people involved and any documents you have. You don’t need to send them yet: a list is enough.
During the call
Expect questions about what happened and what you want to achieve. A good lawyer will tell you plainly if they think you need someone else.
What it isn’t
A first consultation is not legal advice on your full matter, and it does not make the firm your lawyer until you both sign an engagement letter. This is general information, not legal advice.