Collate all the information you have on each source cited in the body of your text. You should only list sources that you have cited in your paper, not ones which you merely read, and have not cited. Try to collect the author name, title, year of publication, publishers and any web address or journal names as applies to each specific source. The aim is to provide the information necessary for a reader to find the same source themselves, so the more information, the better.
Type "Reference List," or "References," or "Bibliography" at the top of a new page. This title should be centered, generally in 12-point font, not in inverted commas, not underlined and not bolded.
Type out the sources using double spacing and a 12-point font. Start with the surname of the author, followed by the first name or initial of the first name for MLA and APA respectively. Input all the data you have, formatting as per the guidelines of the referencing style you are using.
Indent any lines after the first line half an inch from the left page margin---this is a hanging indentation. If the source only takes up one line, then continue onto the next source. Hanging indentations apply to both MLA and APA styles.
Organize your sources into alphabetical order once all the information is inputted. Use the starting letter of the author's surname to place the sources in order. If there are multiple works by the same author, order them by year of publication, starting from the earliest for APA style. In MLA style, the repeated author's name is replaced by three dashes (---) and the rest of the source written out as normal.