For many small business owners, the main focus is on survival -- not growing the business. And, with the freezing of the credit markets and the slowing economy, the sentiment is certainly warranted. Hey, even companies like Google, Inc. (Nasdaq: GOOG) are cutting back.

So, what are some key survival skills? Let's take a look:

Get Paid: It's never fun to call customers who are behind on their invoices and ask for them to pay up. But it's a necessary skill if you want to survive the recession.

Thus, you need to be proactive (for more help on this, you can check out a recent column I've done on this topic).

In a recent piece in BusinessWeek, there's an in-depth look at the revamp of eBay's (NASDAQ: EBAY) website. That is, the company is trying to bring back buyers – who have been moving to rivals like Google (NASDAQ: GOOG), Amazon (NASDAQ: AMZN), and Yahoo! (NASDAQ: YHOO).

It's a smart move and I also think it shows the importance of a key concept: the lifetime value (LTV) of customers.

Generally, LTV involves the following: the profit per unit sold times the average units sold minus the costs of customer acquisition. This should be calculated over a period of time – say 24 to 36 months.

"We actually look at bookings just as much as revenue when we look at the LTV equation," said Jason Blessing, who is a general manager at Taleo (NASDAQ: TLEO). "We feel this gives us a clearer picture of what we are spending to get new year bookings. We feel that we are operating at peak performance if we are getting $2+ in new bookings for every $1 we spend on sales and marketing."