try to prove one major point in each paragraph...and have lots of supporting evidence..specifically exact quotes from a book, etc.
state your thesis at the end of the introduction paragraph, and then re state it at the beginning of your conclusion paragraph
in the introduction, try to generalize your topic, and then get more and more specific as the paragraph goes on, finally leading up to your thesis
*when giving quotes, make sure to say where they came from, what lines,pages, etc
*in your thesis, if you mention a book, include the author...such as "in william shakespeares play entitled ______....
hope i helped! im in the middle of essay writing right now too :-(