Gday Light Chop,
IMHO the main thing to remember on the Nav Display is that a lot of the data displayed is VIRTUAL - not necessarily real. The "magenta line" is very seductive, but not always a true picture.
You MUST absolutely know what on your display is real - VOR/ADF needles, DME etc - and what is virtual - FMC generated.
Of course if you have GPS updating then the whole picture is always close to reality.
The other serious issue is to know what the A/P is trying to do, not what it's programmed to do. ALWAYS watch your flight mode annunciators and know what they really mean.
Enjoy the glass. Most of us would hate to have to go back to the old classic style of cockpit displays.
