MLA (Modern Language Association) style specifies guidelines for formatting manuscripts and using the English language in writing. MLA style also provides writers with a system for referencing their sources through parenthetical citation in their essays and Works Cited pages.
Here are some links that will help you cite sources in MLA:
'Facts are different from ideas: facts may not need to be cited, whereas ideas must always be cited.' - Academic Integrity at Princeton University
When to Cite
Quotation- Any verbatim use of a source, even one word, must be placed in quotation marks and cited.
Paraphrase-Paraphrase is a restatement of another person’s thoughts or ideas in your own words. Don't use quotation marks but do cite the source you are paraphrasing.
Summary- is a concise statement of another person’s thoughts or ideas in your own words. A summary is normally shorter than the original.
Facts, Information, and Data- Often you’ll want to use facts or information to support your own argument. If the information is found exclusively in a particular source, you must clearly acknowledge that source.
When NOT to Cite
Common Knowledge-When facts or information is generally well known and accepted you do not need to cite a source.
Common knowledge does not require citation, but finding the same fact or piece of information in multiple sources doesn’t necessarily mean that it counts as common knowledge.
When in doubt- Cite.
Information taken from "When to Cite Sources." - Academic Integrity at Princeton University. N.p., n.d. Web. 24 Apr. 2013.
There are many ways to avoid plagiarism, including developing good research habits, good time management, and taking responsibility for your own learning. Here are some specific tips:
Plagiarism is presenting another's words, analysis, interpretation or other work as your own. It is intellectual theft, academically dishonest, compromises your reputation and jeopardizes your college career.
Plagiarism is not the same thing as copyright violation. Violating copyright is a legal concept, plagiarism is an ethical concept; you can commit plagiarism without violating copyright and, you can violate copyright without committing plagiarism.
Reuse of your own content such as text, charts or graphs, without attribution. This is considered plagiarism because it does not credit the original source and misleads readers into believing this new, original, content.
Source: "What Is Plagiarism," University of Notre Dame Libraries, https://libguides.library.nd.edu/plagiarism