You must use one inch margins all around. Do not use larger margins. Exaggerated margins give papers an awkward appearance. More importantly they do not compensate for brief or incomplete ideas. Do not use a font larger than 12.
Large fonts give papers a comical appearance.
Make sure you double-space your paper. Single and 1.5 spacing give a crowded appearance. Number your pages. You need only put your name and class time on the first page. Topic sentences should link the paragraph back to the main thesis of the paper or explore a sub-theme of your main argument.