Domain gives you the first clue to bias.
If a website is from a business or intitution with a reputation to protect - the content will be monitored and more accurate than a website authored by someone with nothing to lose.
Domain gives you the first hint of purpose:
.com = commercial
.edu = education
Detailed explanation of Recognizing Bias
What is confirmation bias?
Confirmation Bias: When you only pay attention to resources that support your opinion. Often people don't even realize they are filtering out other opinions and facts. To avoid confirmation bias, get your information from a variety of sources. Look at both pro and con arguements.
The reason for existence creates bias
Bias is not all good or all bad, but it is usually self-serving.
Education related webpages (.edu) and government webpages (.gov) generally are authored by people doing "work for hire" which means they don't own the copyright to the content, their employer does. They are paid by their employer for their time. (Their bias is to keep their job, and not embarrass themselves or their employers professionally.)
Some websites generate money by acting as an organizer for other sellers.(Their bias is commercial...they want you to come back for the ease of access.)
Amazon.com is the most famous one.
Some websites generate money by selling products.
(Their bias is commercial...they want to convince you to buy their product, showing it in a positive light or even to airbrushed perfection.)
Some websites make money by making it easy for advertisers to target an audience. They generate money with click-ads, where every time an ad is "clicked", they get some money.
Health and craft websites are common examples.
(Bias: They have an incentive to provide popular and easy-to-use content to keep you coming back for more.)
Some websites auto-fill their website with content from other websites such as Wikipedia, instead of creating their own content.
(These are usually just trying to get click-ad money, they do not care if the information is accurate or not.)
Whenever a website asks you to identify yourself with information like name, age, income, location, and other demographic information, think about how they can make money off collecting that kind of information. Most people give out correct information by habit, so websites can easily collect reliable statistics about their audience. If they ask you to set up an account, read the fine print in these agreements because they may be using your personal information to make money by selling it to advertisers, using it to attract advertisers, or to generate market research reports, which they can then sell.