Keep a list of all the resources you used in your paper. Write down at least the title and author of the source. You can collect more information later, but it's important to have the sources in one place.
Find out what kind of citation style is required for your research. Some professors require MLA style, while others use the Chicago Manual Of Style or Kate Turabian style.
Alphabetize your source list. Most bibliographies are alphabetized by author; if there is no author, use the editor's name or the title of the work.
Make some templates to follow so you don't have to remember the order to put things. A template for a book citation in MLA style reads "Last name, first name, underlined title. State: city, year of publication." Print out this template and tape it somewhere you can see easily.
Divide the bibliography into separate "works cited" and "works consulted" sections, if you did not quote all your sources in your paper.