Sales copy can make or break your business.

http://www.pamhendrickson.com/download/PamHendricksonCopywritingCheatSheet.pdf
These will vary a little based on your individual business and your goals, but, for me, I always keep a close pulse on 1) the economics of my business, 2) how I support my customers and, one area you may not immediately think, of 3) copywriting.