Websites with .edu, .org, or .gov sites are often more reliable. Be careful of .com sites. Be sure you know WHO is giving you this information.
Creating a correct works cited citation before attempting to do the in-text citation will eliminate confusion when choosing the correct information for an in-text citation.
BEWARE: Although "Noodletools", "EasyBib" and other online citation sites (including citation "HELP" within various library databases) may be helpful, these resources frequently have errors. Therefore, it is your responsibility to make corrections to conform with proper MLA format.
Never cite a source by using only a web address/URL.
Search engines are not sources. Do not cite Google, Yahoo, etc. as sources.
Using Wikipedia as a source for your research paper is at the discretion of your professor. Ask your professor!