While the difficulty of the test might vary depending on where you live (there was more than one town where I grew up that would NEVER pass a boy on the first time, though they never stated it like that, there was just the fact that no boy ever passed on the first time), they tend to look for the following things:
switching lanes (using turn signal), a right turn and a left turn, a proper parking (usually on a hill - remember which way to point your tires!), a parallel parking (usually between cones, not cars), proper stops as stop signs, whether you're using all of your mirrors when you drive, whether you buckle up (and don't forget to make sure they do as well!), and a general check to make sure your car works - brakes, turn signals, defrosts, heat/cool, windshield wipers, lights (and fog lights if you have them), parking break, etc.
Most importantly, try not to get TOO nervous - you'll do fine. If you want, have whoever is helping you learn create a "fake course" with you and having you do most of these things. Remember to keep the radio off, and to make the car as comfortable as possible (don't make it too hot or you'll get sleepy). And make sure the car you're using has gas, I had a friend who forgot that and.....let's just say embarrassing doesn't even BEGIN to cover it. *grin*
It won't be difficult, it'll usually be one policeperson with you. You can answer their questions while driving, but don't feel that you HAVE to talk. You can always hum a song under your breath if it calms you. Let us know how it goes!
Jes