Loving the work is not enough. At the end of the day, you need to get paid. But what if your customers don't cooperate?

It's a common problem that's only getting worse, according to research from the Kauffman Foundation. In a survey released in May, Kauffman found that more than 14% of entrepreneurs had trouble getting paid in 2010, compared to 13% in 2009 and just 2% in 2008. Large companies, which are sitting on unprecedented hoards of cash, are taking longer to cut checks, often revising purchase orders from net 30 to net 60 or longer. In July, President Barack Obama signed an executive order requiring prime contractors to pay subcontractors in net 30, which are the same terms that prime contractors get.

In addition to lengthening payment cycles, big companies are often offering their smaller suppliers an ultimatum of accepting payment in either net 60 or net 10 for a discount of between one and four percent on the total amount due, says Jeffrey Leonard, chief executive of the Global Environment Fund, an investment firm.

"The practice of taking longer to pay essentially sucks available cash out of the small business ecosystem, reducing the ability of small businesses to hire new employees," Leonard wrote in an email.

It's cheaper for large companies, or any supplier, to leave you holding the bag for as long as possible, but that's just bad for your business. It's a vicious spiral: By maxing out your own credit lines and not collecting receivables, you can endanger your bank loan covenants, making it harder to borrow the cash that could tide you over while you're waiting for deadbeats to make good on their orders.

How do you get out of that spiral, and make sure you get paid on time?

Start with a credit check. Do a credit check before you ship any products to any potential customers. Companies such as Dun & Bradstreet will charge you between $90 and $150 for varying levels of reports that include payment histories and creditworthiness.

Northeast Express Transportation, a delivery logistics company with 10 employees in Windsor Locks, Conn., makes sure to get plenty of information about potential new customers, including a thorough search of credit reports.

"We add [a] business only when it’s a good fit for the company and we know that it’s going to be profitable for us," says Kevin Maloney, the company's CEO and owner. "When someone asks for extended terms, it raises a red flag and we know to take a look at their financials."

Once Northeast Express actually begins working with a customer, it conducts periodic credit checks to head off any potential problems.

Ask for bank information. You want to make sure your potential clients have the money in their accounts to handle your order, says John McAdam, a business consultant and professor of strategic planning at University of Pennsylvania's Wharton School. "You have to address bad debt before it goes out the door," McAdam says.

Use purchase orders. Instead of invoicing clients, ask them to send you a purchase order. Purchase orders spell out specifics such as the quantity of items ordered, the agreed-upon price, and the exact payment terms you've negotiated. If there are any difficulties or misunderstandings, a purchase order carries more legal heft than an invoice. The latter can be subject to misinterpretation, and customers can claim they didn't agree to any terms.

Be specific. When negotiating payment terms, remember that net 30 is standard, but spell out when net 30 begins. You can also offer incentives for earlier payment--maybe a 1.5% discount if payment is received in net 15 or net seven days. That's a much better rate than a company would get if they held the money in a standard bank account on their end, says McAdams. Any smart CFO will see that and will likely act quickly.

Get a credit card number. For some accounts, such as those overseas, Matthew Griffin, president and chief executive of Baker's Edge, a Carmel, Indiana, manufacturer of baking pans, will ask for a credit card. Once net 30 arrives, he charges the full amount and sends an invoice marked "paid," he says. He insists on a credit card for these companies because of the difficulty chasing down money in another country. Griffin pays the transaction processing fee. "[It's] a small price to pay for the benefit of certain payment," Griffin says.

Go small. Most entrepreneurs can't resist an order from a really big company. After all, it might take dozens of smaller orders to make up for the one you get from Kmart. But some entrepreneurs are starting to prefer companies further downstream, either mid-market companies or even smaller businesses they know will pay more quickly.

Dynamic Recycling, of La Crosse, Wisconsin, found that its big-company clients were extending payment terms from net 30 to net 45 and even net 60. So it's courting smaller companies that pay faster, or whose business produces better margins. Some of these customers pay in net 15, or pay as much as 50% upfront.

Dynamic, which is number 61 on this year's Inc 500 list, has also refocused its attention on business lines that tie up less capital and where payment tends to be quicker, such as its electronics resale division.

"We’ve decided some business is not worth having when they demand too much," says Miles Harter, chief executive of Dynamic.

Ask. But if you find that enormous order from a large company is just too important to pass up, don't assume they hold all the cards. Make your demands known, experts say.

Griffin, of Baker's Edge, found its catalogue company customers would change terms after a shipment, saying they needed an additional 45 days to pay, instead of the net 30 agreed upon. That meant Baker's Edge had to dip further into its credit line, and pay interest on that amount until the accounts were settled.

"We could not pay back our obligations," says Griffin.

Now Baker's Edge insists on net 30 from the majority of its clients. If anyone wants to try to tweak that schedule, Baker's Edge actually insists on payment before an order goes out the door.

There are other options when dealing with big companies: "Ask for a 15-day payment and an extra point and a half off the invoice, or you could do 2 percent net 30," McAdam says. "If you don’t ask for what you want, you wont get it."