Once you've find a website that you think you might want to use, take a second and think about it--what makes this a good website? Why do you want to use it? If your answer is "because it was the first thing that came up on my Google results" you should probably dig in a little deeper before you use it.
You need to evaluate each piece of information you use to make sure that it has factual, reliable information. A good tool to use to evaluate information is called the CRAAP test. The video below from Western Libraries walks you through each step of the CRAAP test, but some highlights are:
Currency-Is the information still current, and relevant? When was it published? For a lot of issues, information can become outdated, and therefore no longer relevant.
Relevancy-Is the information related to what you are researching? Who was it written for? (If the website was written for children, you probably don't want to use it)
Authority-Think about who the writer or publisher of your website/blog/newspaper etc is. Are they an expert? (Hint: If their name is a screen name like Unicornz4evr, they are probably not an expert.)
Accuracy-Does the author back up their position with facts and verifiable evidence? Do they tell you where they got their information?
Purpose-Why was this information written? is the author or publisher trying to sell you something? Trying to get you to believe something? Is the information biased?
