Lee Hultenschmidt, editor at Dorchester Publishing did a fine blog about good questions to think of and ask an editor when you get the call from an editor.
But I only want to add one thing. Don’t agree to any terms. Tell her thank you for the offer and that you will get an agent and have the agent negotiate the exact terms. As she said, you can’t ask her for agent advice, not cool. You have to hire your own employee.
And remember, just because you don’t agree to the terms, doesn’t mean the deal is going away. It will still be waiting there nicely when in a week or so you hire an agent and the agent calls her.
So read her blog here, note her questions to ask. They are all important to a writer in a contract.