Don't write run-on sentences they are hard to read. Don't use commas, which aren't necessary. Try to not ever split infinitives. It's important to use your apostrophe's correctly. Proofread your writing to see if you any words out.
Correct spelling is esential.
Some of my favorite additions to this list are the following. The passive voice is to be avoided. The Math 696 course pages were last modified September 19, 2001. All rights reserved.