... Code theory, Load calculations, Ampacity factors,Derating for conductors,Conduit Fill,Box fill,Transformer wiring, Business Law, Alarm, and Fire Alarm systems (in NJ)..and alot more than can be listed,... work for a licenced contractor for at least 5 yrs,..apply what you've learned, then take a prep course on the exam..
It ain't easy... Good Luck,
Russ