These are meat & potato questions -- the answers must be satisfying to you. Be sure to ask for things like names, places, dates, products, companies, dollar amounts, percentage of their involvement/contribution. Remember to make them be specific!

• Would you please give me a brief history of your experience?
• What made you decide to become a consultant?
• How did you become a consultant?
• How long have you been consulting?
• What can you tell me about some of your successes?
• How were you involved in those successes?
• What would you look for in a consultant?
• What are your strengths?
• What are your weaknesses?
• Have I explained my needs clearly to you?
• Can you tell me how your experience relates to my needs?
• What projects have you worked on similar to mine?
• How did you become familiar with this market?
• May I see your resume?
• What procedure for working with a client do you typically follow?
  (ie. Amount of phone/personal contact throughout the day or weekly progress reports)
• How do you describe your working style?
• Do you delegate to other associates or will you be doing all of the work?
• What is your follow­up after the project completes?
• What are your expectations of us working together?
• How do you see us working together?
• What's the best way for me to work with you?
• Do you have other projects that might conflict with mine? Either in interest or time?
• How soon can I reasonably expect results?
• What are your fees?
• What kind of guarantee can you offer me?
• May I talk to a professional reference such as your lawyer, your accountant?
• May I talk to satisfied clients?
• Will you sign my non­disclosure/non­compete agreement?
• Do you have any immediate suggestions?