First and foremost, WATCH FOR COLOR BLEEDS!
All usages of color even at the end of descriptions, names, should be ended with &n to return the text color back to normal.
Places to use color:
Places NOT to use color:
Random coloring of descriptions (unless warranted or justified. Example: A white room (bulk 95% of the text white), A permanently dark room/cave (bulk 95% of the text black). This will help keep somewhat uniformity among the theme zones and not overly strenuous on the eyes.
Type help color in the mud to see color codes.