What does the title tell you about the content?
Can you find information about the author?
What is the date? Is there a date?
Who is the intended audience?
How relevant is the resource?
How objective is the content?
Does the author document his or her sources?
The "best" resources to use vary from paper to paper. What is and is not appropriate depends on the criteria you use. A paper analyzing a past historical event does not require that resources be current so old newspaper accounts are an excellent resource. A paper on medical treatments requires the latest information. A current journal article may be the best source for medical research papers. What paper are you researching for this class? Do all of these criteria apply? Which ones are most important for the paper you are writing? Are there any that are not relevant?