One of my favorite books on the topic of student/teacher conferences i s Carl Anderson's How's it Going? There a several sites online (here is one that includes several from Anderson) that can give you a glimpse into the ideas in his book, but in my opinion it is one worth buying.
Anderson's book covers everything - including what other student are doing while the teacher is conferencing. If you have been teaching for very long you know that this concept is super important. So, on day's like today, our warm up is all about the do's and don't's of conference days.
I will remind students that they fall into two categories over the next two class days - waiting or moving on. If they are "waiting" to be called up for a conference, they should be preparing their prewriting sheet. If it is incomplete we cannot have a productive meeting and I may send them back. If their sheet is complete and they feel confident about that, they may read independently. If they are "moving on" they have already conferenced with me and have specifics to move on to based on our conversation.
I also remind students that they are not to interrupt while I am conferencing. Middle school students tend to think their problem is the most important in the whole world and want it addressed immediately; however, my attention is 100% with the student I am conferencing with, so to curb this, I deduct time from their afternoon break/social time if they interrupt. They will appreciate it when they are the one getting my full attention.
I quickly move from our warm up discussion to conferencing because I know the minutes are precious if I am going to spend quality time with each student over the next two days.
During conference time, I keep a check list of where students are and we make notes on the prewriting sheet to remind the student of what we discussed and any next steps.
When students return to their seat, I want them to have a plan they can attack on their own.
To wrap up class today, I will pull the class back together to address any questions, allow students who have conferenced to share out and remind students who were not seen today that tomorrow is their day.