Having never used Just for Starters before, the leader's guide was very helpful. It consists of the exact same study as the ordinary booklet, but with loads of space for extra notes and lots of extra cross-references for each question, if you need them. The key thing, though, is a series of audio talks on two CDs by Tony Payne, covering introductory matters and then each for the seven sessions. I found it best to copy them first to computer.

Tony speaks very clearly, teaching you the background to the matters taught in the session so that you are confident you have a good grasp, beyond just the study questions. He then takes you through the study itself, so at least you know you've got the answers right!

I haven't come across this concept as a study guide before and found it really helpful to take notes on what he said to add to my own notes.