I was trying for 10, but couldn't come up with others, please chime in if you have any suggestions;

In no particular order:

1. Proofread or at least double check the document before printing!
2. Print double sided (duh!)
3. Check to see if you can print in a draft form, many times this is just as good as higher quality
4. Don't make extra copies unless needed
5. Email the document, if you don't want people to be able to edit it, turn it into a pdf
6. If you are using a color printer, see if your printer has the option to dectect color.  If it does, use it on your color documents that are mixed with black and white pages.
7. If your last page of printing is short, try adjusting the format or margins to condense the document