There is no single way to evaluate a source for reliability or appropriateness. Instead, we must ask many questions of each source. Below are some ways we can look at a source to evaluate it.
"Information resources reflect their creators’ expertise and credibility, and are evaluated based on the information need and the context in which the information will be used." 1 Framework
Whether something is important or can be viewed as an authority depends on the situation you plan to use it in. A tweet about a political policy isn't generally something we would cite. But if the president is the one tweeting it, how does that change the context? A famous speaker might lend authority to a particular management technique, but if they are trying to sell you training materials on that technique from a company they own, does that change our trust in their authority on the topic? If a peer-reviewed article uses an experiment to support its hypothesis, but the experiment was funded by a corporation with a conflicting interest, does that change how reliable we think it might be?
When looking for research on a topic, remember currency affects what format it may be published in. If it has just happened there will be no peer-reviewed, analytical sources. Can you instead use a current news source and an older peer-reviewed source on a similar topic?
Every time we evaluate a source we must ask these questions of it--news source, journal article, website, or something else entirely--to determine whether it is a source we can trust to serve the necessary purpose.