A helpful way to identify credible sources is to apply the CRAAP test to the information you find. Consider these criteria:
Currency - When was the information published? If it is a website, when was it updated? Does your topic require current information?
Relevance - Does the information relate to your topic? Who is the intended audience? Look at other sources on your topic; how does this fit in?
Authority - Who wrote, published, or sponsored the information? Where do they work? What are their credentials?
Accuracy - Where did the information come from? Does it include references? Is it peer-reviewed? Is the language scholarly?
Purpose - Why does the information exist? To inform? Entertain? Sell? Can you detect any bias?