How do companies maintain margins in this economy?

I was asked the question yesterday “How do companies maintain margins in this economy?”
I think it was the wrong question. The right question was how maintain cash flow and preserve cash in this economy.
Forget income, just work on cash flow. Here is how:
•    AR: Everyone I know seams to be having issues with late payments (over 90 days not being unusual). This is one of the most important issues to work on. This is not the time to be understanding.  Use any leverage you have to make sure you are the one who gets paid first.
•    Contact your customers, work on your relationships, and ask them for referrals.
•    Make sure you know which customers or products are the real moneymakers for you. If you have a marginal customer or product, now maybe the time to ditch them.
•    Clearly control spending