Informative abstracts can substitute for the original literature in many cases. Abstracts can be used to help organize the preparation of articles, reviews and bibliographies. Includes salient data from the original work. Follow the same order of presentation as the original. Use the outline or table of contents as a guide.
Length depends on the nature of the original.
Be as brief, but complete, as possible. Avoid redundancy, repetition, circumlocution. Be clear and unambiguous. An abstract should enable the reader to decide immediately whether or not to read the original. Use active verbs, short and varied sentences, non-technical language.