Authority & Credibility - Who specifically wrote the source, or who is responsible for publishing it? Why should you care what they say? How do they describe themselves? And more importantly, what do others think about their credibility?
It’s usually more important who is responsible for publishing the information, rather than the individual author. If the writer isn't in the employ of whoever published it, then you will see a brief biography.
How can you find out the reputation of the magazine, newspaper, or organization that published the information? Google the name to see what others are saying. If it is a real news organization, there will be a Wikipedia entry on it.
A very useful tool for a thorough evaluation of news organizations and major think tanks is NewsGuard. It's a subscription service, but if you use the Microsoft Edge browser (desktop or app), you can download the extension for free.
Go to https://www.newsguardtech.com/edge within the Edge browser, for directions about adding the extension.
For the App version, go to the Microsoft Edge settings, and click on News ratings. Turn it on. When there is a rating for the news site, you'll see the icon in the address bar.
Once you have NewsGuard installed, you'll see a green, gray, or red icon next to the results list in Google, or at the top next to the URL when you are on a site that NewsGuard has evaluated. Hover over the icon to bring up a short evaluation of how well it follows journalistic standards. Click on "See the full Nutrition Label" to view a detailed analysis, with references.
Evidence - What is the evidence? Is it complete, or does it have holes in it? Is it balanced, or overly biased or slanted?
Some sources will be relevant and useful, but do not give the reader a complete picture of the issue and ramifications, such as an editorial that is slanted to a particular perspective. But just because a source is not balanced does not mean it would not be useful. It just means you need to find sources with other viewpoints as well.
How does the information compare to others? Similar, or an outlier?
This you won't be able to judge until you've read several sources...