ARE YOUR SOURCES...
When was the site created, the book published? Has the technology changed or new information become available since then? Are links still live?
Who is the author and what is his/her expertise? Who publishes the site/hardcopy - a university, business, organization, individual?
What is the stated purpose of the site? (Read the site's About link if there is one). Is the information supported? Is it verifiable fact, or is it opinion? Does it seem that important information is left unstated? Are counter-arguments acknowledged and fairly treated? Do they have an axe to grind or something to sell? Is the language hyperbolic or emotional? Who do they link to or cite?
How well is the information covered? Are there credible supporting links or sources cited?
Do they answer your questions and help develop and support your thesis or what might become your thesis? (Remember, while you need a general idea and direction, you don't have to know your thesis at first but can develop it as you research, and even as you write early drafts).
YOU MUST CITE IF...
1) the information, idea, insight, or concept is from another source. Paraphrased information must be cited. Just as you want credit for your achievements, you must give credit to the thinker, artist, writer, or researcher who found or created the information you are using in your paper.
2) you are quoting directly. Use phrasing like, According to Perez, "The English sonnet...."
YOU NEEDN'T CITE IF...
1) the information is universally established: "The sky is blue." "Abraham Lincoln was President during the Civil War."
2) it is your opinion or experience.
REASONS FOR CITING...
1) To claim someone's original research, words, or insight as your own is intellectual theft.
2) To validate your claims.
3) To provide a helpful trail for those readers who wish to pursue your topic.
1) A few quick tips:
2) Date the drafts of your paper as you revise.
3) Keep back-up copies of your paper.
... and REMEMBER...
as a general rule, you are basically citing twice in your paper: a) in-text citations which give quick, immediate information about your source and b) a Works Cited (MLA) or References (APA) page at the end of your paper which gives more thorough, bibliographic information about your in-text citations.