First, think of the authority of a website.  Generally, .gov and .edu websites are considered the most trustworthy, as they are from government and educational institutions. If the URL ends in .org, it is a non-profit organization, and if it ends in .com, it is a company.  These entities could provide questionable content that might not be suitable for research.

Bias is how a person, organization or website may be prejudiced or lacking in balance.  A good example would be a .com website that is telling you how good a product is.  Do they have an economic interest in the information they are presenting?  Even .gov or .edu websites can be biased, so you should always be considering bias.

Analyze the content of your website.  Do they reference their claims and cite their sources?  Does the quality of information presented reflect a professional approach to the subject?  Does the website list their authors and their credentials?

The currency of a website matters.  Is the website updated regularly?  Does the article have a listed publication date?  Is the information current?  Make sure to consider the date when evaluating your resource.