When conducting Nav training, whether it be PPL, CPL, CIR, Charter, Airwork, day or night
if you find yourself with nothing to do, chances are there is something you should be doing.
Log complete, fuel calcs and tank selections, GS checks, Radios (upcoming freq etc), Approach review (if Instrument rated) if coming up to an AD with established approaches, even if you may not have to do one, get into the habit. Obviously most of this should be included in TopD and TopC checks, so make sure they are done properly.
This will help immensely in keeping you ahead of your aircraft.