The most important thing is to know what questions to ask when reviewing a source. The more research you do, the more of a habit it becomes! Here's a handy mnemonic for remembering some of the most important questions to ask:
The CRAAP Test
C - Currency - Is the information in this source current, or has it become outdated?
R - Relevance - Is the information relevant to your research question or topic? And is this kind of source appropriate for your uses?
A - Authority - Who's the author and what are their qualifications? How do they know what they're telling you is accurate?
A - Accuracy - You might not know right away if the information is accurate - after all, that's why you're researching it - but there are some flags you can watch out for. Are the claims supported by evidence, and are sources cited? Are there editors or peer reviewers? Do any other sources support or verify the information?
P - Purpose - Why is this information out there? Does it appear impartial or biased? Are the authors or the publisher trying to present facts or to convince you of something?
(The CRAAP test was originally created by the Meriam Library at California State University, Chico)
For a deeper dive into some good questions to ask - helpful to read through when beginning your research, so these considerations are fresh in your mind - check out the UC Berkeley Library's guide.