2. Prepositions are not words to end sentences with.
3. The passive voice is to be avoided.
4. Avoid cliches like the plague. They're old hat.
5. It is wrong to ever split an infinitive.
6. Writers should never generalise.
Seven: Be consistent.
8. Don't use more words than necessary. It's highly superfluous.
9. Be more or less specific.
10. Exaggeration is a billion times worse than understatement.
For more excellent tips go to Writing and Maths Skills Online.