I still don't feel I've mastered the art of asking good questions, because each client and each project requires a unique set of questions for the same information. And each question must be clever enough to capture the right response, which yields the best kinds of information.
I'm not there yet. But I've learned, over the years, that it's okay to ask follow-up questions to ensure that I get what I need. And I've learned that although questions gather facts, good questions gather the reasons why, opinions, feelings, and expectations which project objectives rarely include. And it's these items that add fuel to creative solutions.
For example, instead of asking, "Who is your target audience?" ask, "Who do you feel in your audience is the most critical to the success of this project, and why?" The first question will get you important facts, but the second question will get you more accurate facts, emotion, and expectations for the project.
Instead of asking, "What response are you expecting?" try asking, "What message should really resonate with your audience?" It's good to know that your client wants his audience to ask for literature, or to be motivated to buy. But it's even more important to find out what the client really wants to communicate to his audience — even if it's to get the literature for some emotional, reasonable, or compelling reason, she has in her head.
And for a final example, instead of asking "What message should your project get across?" ask, "What message should really resonate with your audience?" Again, you go behind the information to the what really matters to your client.