Read the Abstract/Summary first. This will help you determine whether the full content/article will be relevant.
Once you begin to find information, you need to evaluate it to ensure its appropriateness for your research.
Use these broad criteria as a guide for checking the quality and relevance of your sources:
Reliability of the source: Is it from a scholarly journal, textbook, trade publication?
Authority of the author: Are they qualified, experienced, affiliated with an institution?
Accuracy of the information: Are all reference sources listed, spelling/grammar consistent?
Currency/Timeliness: is the information current or historical information?
Point-of-view: is a particular viewpoint expressed? Is bias or opinion evident?
The web provides access to seemingly unlimited amounts of information. However, the information you find may not be appropriate to be used as a base for your assignments, or for your research purposes.
There are numerous, useful web evaluation checklists available on the web - created by authoritative institutions. Here is one example.
An important point to consider: all information used for research or study purposes (whether it's web-based, televised, broadcast, or formally published) should be thoroughly vetted before deciding to use it in your work.