You want to think critically as you're evaluating resources. Here are some things to keep in mind:
Source
For this assignment, you need academic sources. Generally, these are books published by scholars in specific fields or articles in scholarly journals. This also includes peer reviewed articles. These articles are anonymously reviewed by multiple experts in a specific field. While it's not always the case, generally you'll find more recent research in scholarly journals. Peer-reviewed resources are usually considered the best scholarly resources, but you'll still want to be critical about each source you find. Even peer-reviewed resources can be out of date (in medical fields, for example).
Author/Authority
Take a look at the authors' affiliations. Do they have degrees in the field in which they are writing? Are they affiliated with specific groups that could cause any sort of bias? If so, have they indicated any conflict of interests - are they being transparent about it?
Publication Date
In some fields, the publication date may not matter for research. However, in fields like medicine, the more recent research is usually the best option (unless you're researching medical history). Also, pay attention to the publication dates of included citations within a resource. If a resource published in 2015 only has citations from 1985 or earlier, ask yourself why that is? Does it make sense for the resource, or is there more recent research that's missing?
Image from the xkcd webcomic: https://xkcd.com/285/
Citations and Evidence
Academic resources will provide citations and evidence. Citations are vital for readers to track back to primary sources, pieces of evidence, and research threads. If you're reading something without citations or provided evidence, think carefully about it's reliability. When you're doing an in depth evaluation of a book or article, you'll want to track down citations provided by the authors. Tracking down these citations will help you determine if you agree with specific uses or interpretations of resources or if you want to utilize those resources in your own research.