Know exactly how much money you need to stay in business--everything from rent, electricity, and worker's comp insurance to coffee, toner cartridges, paper, and even how much you pay your tax preparer. Divide that number by the number of days a year that you're open for business, and that's your "nut"--the minimum amount of money you need to bring in every day. Keep track of it on a daily basis: If you have a lot of days where you don't make your "nut," you need to rethink things.