I came across this blog post today during halftime of the Kansas City Chiefs game. I thought it was a good comparison of conferring. I might add that yes you must  listen to the student and let them lead the conference(you must train them to do this), but also know what your focus for the day is, and to check and see if the student can apply it to what they are reading. Conferring is a great informal assessment tool. You may or may not be able to ask a student to apply the days focus depending on what they are reading. That being the case you might want to send students off to finish reading and reflecting on a piece of text that you handpicked to practice the focus/skill before they dig into their book of choice. You can always ask the student to talk about that piece as well as their book of choice in your conference with them

Read, Write, Reflect: Lessons on Conferring