For each source you encounter, ask questions of that source.
Who created this source? For what purpose? Is it believable? Does it meet my need?
An easy way to remember the key questions, use PROVEN.
Another way is the neighborhood idea from Choosing and Using Sources.
Visualize the web as a community. (Image source: John Atkinson, Wrong Hands)
The Web has an abundance of information for you to sift through. The following video may help you evaluate the reliability of the sources you find.