I have struggled to find an efficient system of documenting my conferring sessions with students during my Readers' Workshop. I want to have enough information, but not so much that it limits how many students I can meet with per day. This form has worked well for me.
In addition to the regular components of a reading conference, I also take the opportunity during this one-on-one time to confer with students about what they are writing about in their reader's notebook. I find it provides just the right amount of regular, individualized instruction to guide students toward better quality in their "Writing About Reading" goals.
If you are interested, my shop also has a rubric for assigning a holistic score to the Reader's Notebook.