What would you like us to do? What is the overall goal of the project? Who are you targeting?
How many pages of web copy/ brochures/ articles/ blog posts/ press releases/ case studies...
What do you do, how large is the company, where are you based, when were you founded? Why were you founded? What are your business goals?
What does this person listen to...wear...read...watch...?
Who are you are trying to reach? What problems do you help them solve?
Who are they? How is your brand different? What do they do better or worse than you? What do you admire about the competition?
What channels do you use? What is proving most effective? How do you feel about your current tone of voice - does it reflect your brand?