You may think . . .
"It's published, so I can use it." Well, maybe. If it's published by a legitimate publisher (the books and magazines in the library are!) or if it appears in a database, the information is more likely to be reliable. But it might not be a good source because of its focus, publication date, or type (for example, a popular magazine if your instructor wants you to use a scholarly journal).
"It came up on the first page of results when I searched the database." Hold on! Many databases put their results in date order. What comes up first are the most recent articles. They may not be the ones that are best for your research.
"I did a search on Google, and it was one of the first sites, and Google has relevancy ranking." Slow down! Searching on the Web brings you face-to-face with the need for evaluating sources for reliability AND appropriateness to the project. Look at those sites critically!
The SMELL Test
S is for Source. Who is providing the information? Are they qualified to speak about this topic?
M is for Motivation. Why are they telling me this? Does the author have a bias or financial motive?
E is for Evidence. What evidence is provided to back up the author's claims?
L is for Logic. Do the facts logically lead to the author's conclusions?
L is for Left out. What’s missing that might change our interpretation of the information?