"Good" sources include those that provide complete, current, factual information, and/or credible arguments based on the information creator's original research, expertise, and/or use of other reliable sources.
Whether a source is a good choice for you depends on your information needs and how you plan to use the source. For verifying facts and claims, you'll want sources that help establish what happened or what's true. For developing arguments about complex or debatable topics, you'll want sources that represent different expert perspectives and high-quality reasoning.
Evaluating Sources Using Lateral & Vertical Reading
The SIFT* & PICK approach to evaluating sources helps you select quality sources by practicing:
Lateral Reading (SIFT): fact-checking by examining other sources and internet fact-checking tools; and
Vertical Reading (PICK): examining the source itself to decide whether it is the best choice for your needs.
SIFT works well for verifying individual facts, but not not as well for interpreting what those facts mean. When experts disagree about complex issues, your job shifts from fact-checking to evaluating different arguments and developing your own well-supported position.