Finding information today is hardly challenging. Type in some terms into a search engine and boom! The challenge is to find high quality information that meets your specific needs. Be very picky!
Here are some questions you should ask yourself when you are sifting through your web search results, looking for gems of information.
Authority or Investigate the Source - Who wrote it or who is responsible for it? Why should I care what they think?
First, determine who is most responsible for the information: the individual author or the organization. Unless the information is scholarly (see below for criteria for that), it is more important to judge the authority of the organization who published the information on their website, rather than the individual(s) who wrote it.
Look for an "About Us" tab or link.
Try looking at the top or the bottom footer on the homepage. Determine how long the organization has been around, what their mission is, etc. Why should anyone value their viewpoint? Note: Sometimes the organization isn't very detailed, because they assume you already know all about them.
What do others think?
Realistically, anyone can say anything they want about themselves. What's more important is what others think.
Date - When was it written?
How important this criterion is depends on your topic. Your instructor may set limits on the date range you may use for your sources. The harder part for some websites is locating a date...
Comprehensiveness - How complete and balanced is the information?
Some sources will be relevant and useful, but do not give the reader a complete picture of the issue and ramifications, such as a blog post that is slanted to a particular perspective. The more comprehensive sources (and therefore the lengthiest!) will be especially useful at the beginning of your research, when you are still absorbing as much as possible about your issue.
But just because a source is not balanced does not mean it would not be useful. It just means you need to find sources with other viewpoints as well.
Evidence - What evidence does the source use to back up assertions? Is the information sound? How does it compare with other sources?
This is the most important criterion to judge your source. But it is the one that takes the most time, because you have to know enough about your issue to judge the soundness.