Always double-space college papers unless instructed otherwise by your professor. Use a common 12-point font. Set your margins to one on all sides. If you try to deviate in spacing or in margins to make your paper look longer, it could detract from the work you've done.
Leave the plastic binders at home. Simply staple your paper in the upper left hand corner and leave it at that. Number all pages but the first, to make it easier for your professor to comment on certain pages.
Make sure that you cite the original page numbers of any source you use. If you are getting the source from somewhere it has been quoted, either find the original source or find the page number in the citations provided. Unless otherwise instructed, cite your sources on an unnumbered page at the end of your paper.