See the "MLA Overview, Formatting & Guide" 
from the Purdue OWL Writing Lab for detailed help.

Generally, citation information usually includes:

• author(s)
• date of publication
• title
• publisher's name and location
• (and for articles: journal title, volume, issue and page numbers)

TIP: Many article databases have a built in option to email citations formatted for MLA style.

Citation management software will let you save, organize, format and share citations from a variety of sites (e.g. library catalogs, article databases, Amazon etc.) and create bibliographies and cited reference lists using citation style formats (e.g. APA, MLA, etc.)

Software:

• Zotero
  • Support page
  • Quick Start Guide (video introduction)
  • Installing additional Styles
  • Zotero guide @ GSU
• EndNote Web
  
  
• Zotero versus EndNote Web (Pros and Cons)

Plagiarism is presenting the words or ideas of someone else as your own without proper acknowledgment of the source. When you  use supporting material from works by others, it's okay to quote and use their ideas, but you need to correctly credit them. Even when you summarize or paraphrase information you must acknowledge the original author.
Tips for Avoiding Plagiarism:

• Use your own ideas - it should be your paper and your ideas that are be the focus
• Use the ideas of others sparingly - only to support or reinforce your own argument
• When taking notes, include complete citation information for each item you use
• Use quotation marks when directly stating another person's words