If you cannot answer all or most of these questions, the information may be a bit fishy.
(Click to expand each section)
Strategy: In a book, look towards the front for the publication year or copyright date. For an article, look at the top or bottom for a date. For a website, look at the top or bottom of the webpage.
Strategy: Do a Google search for the author's name and analyze the results.
Strategy: Search for an article, book, or website on the same topic and compare the information in both sources.
Strategy: Look at the content. Do you feel that it provides enough information and will be helpful for your topic?
Strategy: Read the text. Does it seem like the content simply conveys information, or is it trying to persuade?