Answer:
Look at the author. Are they educated in that field, or are they just giving opinions
Look at where the source came from. Websites that end in .com are less reliable than websites that end in .gov .edu or .org
these sources are typically websites that directly research the material being quoted.
when was the source written? Current information is more accurate. For example, The article about cancer treatment from 50 years ago will not apply today.
was there extensive research on this topic? the more research the better. Typically, you want at least three studies or sources to confirm truth