I’m probably the opposite of the graphic designer who “talks too much”. I feel like I need to encourage myself to talk more because otherwise I’m not participating in the process enough. But more often than not, the client is willing to talk at great length about what they are looking for, so I find that the cure-all for me is (as you suggested) to ask questions. It gets the dialogue going and ensures that you’re getting as much information and ideas as you can.