What do I need to know before taking the home owner's electrical test?
First this varies by municipality.  Almost all municipalities use a multiple choice test and mine did not.  

I would say key things you should know:


Definitions.  You need to know what terms mean so that you can find the answer with the right context.
Understand the basic electrical equations.  Power, ohms, watts, cable requirements...
Understand what each section of the guide covers.
Understand how to properly find things using the gloassary.
Have a good understanding of basic electrical code.
Be good at math.  A lot of questions require math skills.  
Understand how to diagram basic things like 3-way switches, laying out outlets in a room, a switched light, a ceiling fan with controls for light and fan, gfci switches...


Extra Note - I passed.  So if you have questions shoot me an email.