1.  Understanding what they want: Don't leave it up to them. Frame your question with set limits, i.e. "In 20 words or less, tell me your point." Or "Tell me in 20 seconds or less what you hope to accomplish with this piece. If it takes 25, you're still listening!

2.  Questions you don't want to answer: Most writers have the exact same problems. They don't know what to write and/or how to say something. At the same time, we've all been encouraged to have someone else read what we've written for feedback. As a result, many clients will have the same questions, including asking what you think about their writing. One way to not answer these questions but still help is to use the psychologist ploy of asking the client, "What do you think?" thus putting the onus back on them for an answer. Another is to simply tell the client that the answers you would give would be yours, not theirs, and the answers to these questions need to come from them.

3.  Burn-out happens in many jobs. Try to approach each client as a different project with a different set of circumstances. View similarities that you encounter in problems and questions as the "easy stuff." You've seen or heard it before, and can handle it. That leaves you to concentrate on the "tough stuff;" solving the meaty issues that leave you with a sense of accomplishment. Like any expert in any field, you are going to have to answer the most common questions an uncommonly large number of times. It goes with the turf. But, because you already know the answers, it allows you more time to focus on what really matters.

Years ago, I had a job where every single person who came to see me asked me at least one of 8 questions. How did I find that out? I wrote them down and put a tick next to them every time they were asked. I found out what the most common questions were, and had a visual record to show for it. Maybe take it upon yourself to do the same thing for the Writing Center. Write down those "frustrating" questions, and check them off whenever they're asked by a client. (Possible side benefit: If they see you do it, they may ask you what you're doing, and you can tell them!) Before long, you can share your "research" with your fellow consultants and/or produce a handout of the "Questions you must ask yourself" to give to your clients in your first meeting.

Good consulting!

I notice that I tend to give the same response to clients, which makes me nervous.  Though I doubt that all writing can be reduced to explaining meaning and why, it seems that most of the time having my clients answering these two questions usually solves most of the coherence issues they struggle with. It's not a guaranteed tonic, but it seems to make sense to them. But I wonder if this is just a crutch I use that avoids engaging them in a more productive way.