In order to avoid plagiarism, you must give credit when
You use another person's ideas, opinions, or theories.
You use facts, statistics, graphics, drawings, music, etc., or any other type of information that does not comprise common knowledge.
You use quotations from another person's spoken or written word.
You paraphrase another person's spoken or written word.
Begin the writing process by stating your ideas; then go back to the author's original work.
Use quotation marks and credit the source (author) when you copy exact wording.
Use your own words (paraphrase) instead of copying directly when possible.
Even when you paraphrase another author's writings, you must give credit to that author.
If the form of citation and reference are not correct, the attribution to the original author is likely to be incomplete. Therefore, improper use of style can result in plagiarism. Get a style manual and use it.
The figure below may help to guide your decisions.