-Taken from p. 72 of Teaching Information Literacy: Threshold Concepts Lesson Plans for Librarians, Chapter Three "Determining the Relevance and Reliability of Information Sources"
You may have heard something along the lines of
This rule does not work. Do not follow it.
Instead, use the tools I laid out in the box above this one. You must consider each resource on a case-by-case basis. Each kind of resource has its own types of biases and best uses.
Below are a few links that I think many of you will find helpful. These are not the only sources you can use online, but they may be helpful places to start.