The MLA Handbook provides formatting guidelines, but allows for professors to set their own guidelines as well. Always follow your instructor's directions before applying any MLA guidelines. (MLA 1)
Keep in mind that sometimes there can be more than one correct way to cite a particular source.
The rules for authors are the same for no author and multiple authors; the format (book, journal article, website, etc.) does not matter.
For no author, skip it, and begin your entry with the title.
For one author, use Last Name, First Name.
Nelson, Gil. Trees of Florida. Pineapple Press, 1994.
For two authors, use Last Name, First Name, and First Name Last Name. Put them in the order presented in the source, not alphabetical order.
Kennedy, Eugene C., and James D. Smith. The Unhealed Wound: The Church and Human Sexuality. St. Martins, 2001.
For three or more authors, use the first author presented in the source and et al. Last Name, First Name, et al.
Kyle, Chris, et. al. American Sniper: the Autobiography of the Most Lethal Sniper in U.S. Military History. W. Morrow, 2012.
Single names may be used as authors, e.g. Homer.
Pseudonyms, stage names, and screen names may also be used as authors. e.g. Beyoncé.
Editors and Translators go either after the title of the source or after the title of the container, depending on which work they have edited or translated. For example,
Euripides. Medea. Translated by Gilbert Murray. Project Gutenberg, 2 Mar. 2011, www.gutenberg.org/files/35451/35451-h/35451-h.htm.
In the case above, Gilbert Murray comes after the title of the source because that's what he translated. It would make no sense if we put it after Project Gutenberg because he didn't translate everything in Project Gutenberg -- just that one work.
Here's a second example:
Euripides. Medea. Three Plays of Euripides, translated by Paul Roche, Norton, 1974, pp. 33-77.
In this second case, Paul Roche appears after the title of the container because he did translate all three of the plays in the book.
Editions go in the version slot in between contributors and numbers.
Lipson, Charles. Cite Right: a Quick Guide to Citation Styles -- MLA, APA, Chicago, the Sciences, Professions, and More. 2nd ed., U of Chicago P, 2011.
In this case, there are no contributors and no numbers, so the edition comes between the title of the source and the publisher.
Permalinks are permanent URLs, usually only an issue in databases. This is because databases tend to use dynamic URLs that change each time a search is executed. A dynamic URL will only work for the duration of a session. To reliably return to a resource in a database, a permalink is usually needed. A permalink always returns to a particular article.
For URLs, omit the http:// or https://. Shorten URLs that are longer than three lines OR that are longer than the rest of the entry.