The following guidelines are given in Mark Twain's satirical essay, "Fenimore Cooper's Literary Offenses," and were selected from a larger list.
Any writer, but especially students trying to write acceptable essays or other prose for a grade, would do well to follow these rules.
1. A tale shall accomplish something and arrive somewhere.
2. Episodes of a tale shall be necessary parts and shall help develop it.
3. Crass stupidities shall not be played upon the reader [as "sophistication" or "scientific truth"] by either the author or the people in the tale.
4. Events shall be believable.
5. The author shall: Say what he is proposing to say, not merely come near it.
6. Use the right word, not its second cousin.
7. Eschew surplusage.
8. Not omit necessary details.
9. Avoid slovenliness of form.
10. Use good grammar.
11. Employ a simple and straightforward style.
For full text see here: http://users.telerama.com/~joseph/cooper/cooper.html "The time to begin writing an article is when you have finished it to your satisfaction. By that time you begin to clearly and logically perceive what it is that you really want to say."
- Mark Twain's Notebook, 1902-1903