If you want to maximize your test grades, then these resources can help. The first is a 47 slide PowerPoint dedicated to all things radical. Covers the entire unit, including practice questions with answers. Get it here.
This document lists the most common mistakes (and how to correct them), when calculating radicals and solving radical equations.
The final links today are for two of the many tutorial videos available on this site. Scroll down the sidebar on the right. This video covers simplifying radicals. A more difficult topic, conjugating radical denominators, is covered here. Both are < 5 minutes long and very helpful.