The following short video describes the benefits of using library resources and specialist databases, rather than just using Google!
Different sources can be used for different purposes. Some such as Blogs and Wikipedia may be useful to give you background information to help you gain an understanding of your topic but it will not be acceptable as a reference to support your assignment. The youtube below outlines what a scholarly or peer reviewed source is. If you need to verify if your source is peer reviewed you can use Ulrich's Periodicals Directory.
The CRAAP test had its origins in the US to help students successfully evaluate and find reliable information. The test has seen many variations but in general if something is CRAAP, that's a good thing! CRAAP stands for:
These are the types of things you want to check for, regardless of source type (books, articles, web sites, blogs, etc.) The following YouTube by Western University gives a brief overview of applying the CRAAP criteria and the full criteria can be found as a pdf here
When researching you may be looking for both scholarly material such as that found in library databases (Summon) and Google Scholar as well as authoritive government sites and geographical information which can be found using Google. Each of the search tools is useful for different purposes.