You may not be aware, but you can prepare for your Canadian citizenship test online by taking sample tests directly from the CIC. While other sources of citizenship preparation are available, it's important that you ensure your preparation comes from the CIC citizenship guide, Discover Canada, and that any tests you practise with are also based on that material.
Here's an official list of study questions you can use for your own preparation.
For those of you with an Android device, the app, How Canadian Are You, Eh? is the CIC's official test preparation tool, and the one I personally use.
The actual test is comprised of 20 multiple choice questions, and most of these tools simulate the real test.
Luck favors the prepared! Get studying!