If you've started an enterprise startup, you already know that a substantial sale to a large customer is a very big deal. It will mean a hefty infusion of cash, or perhaps a steady stream of revenue, and that's only the beginning.

With that large customer's implicit endorsement, landing other customers large and small will get a lot easier. So will obtaining investment money and bank loans. This single sale can make the difference between a successful venture and a short-lived one. It's one of the most high-pressure moments a new company faces.

Matthew Bellows, CEO of Yesware, was under exactly that pressure when he set out to land Groupon as the company's first big customer. Yesware helps salespeople track email communications and integrate them with Salesforce. Making that first big sale helped the company grow to 200,000 users, and put Yesware on its way to success.

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How did he do it? Here are some tactics that added up to a powerful strategy:

1. Get your product into users' hands. If there's any way to get your big customer's users to try out your product, do it. Yesware decided to take a “freemium” approach, providing a free level that lets salespeople thoroughly try out the service before paying for it. The result was that Groupon's Sanober Mukadam came calling. “A lot of our sales reps told me I had to try it,” she says.

2. Pay attention to SEO. Big customers want to do business with other substantial companies, so you need to project that you're a serious company and be easy to find. Yesware's strategy is to frequently update the site with blog posts and articles useful to salespeople. Smart move. “Sanober found us by Google searches,” Bellows says.

3. Know how you fit in the marketplace. Don't insult a big customer's intelligence by telling its executives that there are no other products like yours. That's almost certainly not true. Instead, when Bellows first met with Groupon execs, he presented a spreadsheet showing how Yesware compared to other email software for salespeople. The idea wasn't that it could be all things to all salespeople -- instead he showed what the software's particular strengths were as well as what it couldn't do.

“It helped shorten the sales cycle,” Mukadam says. “We knew exactly what the company was about."

4. Have no secrets. This can be a challenging step for any company, large or small. But it was a big part of landing this sale.

“Another thing Matthew did was understand how the product fit in the marketplace in terms of pricing,” Mukadam says. “He surveyed the market to see what companies would pay for a product like this and he shared that information with us and told us what his pricing was based on.”

Bellows adds, “The radical transparency approach is more and more required for sales. You get a lot of benefit from sharing what used to be considered sensitive information with a customer. It's a way to stand out in a crowded marketplace.”

Transparency can be a two-way street. “There was another company offering a big discount to our finance team,” Mukadam says. “This was all openly talked through."

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5. Make creative requests. What can a large company offer you besides money? Lots of things, most likely.

For instance, Bellows says, “They worked with us on a press release and helped us raise our B round of funding.”

Items such as these are easy for a large company to provide. After all, if they’re your customer, they want you to be around for a long time.

6. Say thank you. Naturally, Bellows made sure Groupon had a great experience with Yesware by handling the engagement himself and bringing Yesware's engineers to talk with Groupon engineers so that the two companies could work together most effectively. But beyond following through with a stellar experience for the customer, Bellows says, don't forget the value of a simple, personal expression of gratitude.

“It can be a card or a bottle of wine or flowers with a handwritten note,” he says. “It's the willingness to reach out and stay engaged.”

7. Don't let them turn you into a one-customer company. When a small company sells its product to a large one, there's always a danger of being turned into what Bellows calls “a consulting shop.” That can happen if you alter your product in ways that will only serve that particular customer. You may be extremely eager to make the sale, but resist that temptation, Bellows says.

“Make sure everything you build for one customer is something you can sell to at least a couple of others,” he advises.

In fact, before Groupon, Yesware came close to making its first big sale to a different company. But that company presented a list of features that it required before rolling Yesware out to its sales reps.

“Much as we wanted the deal, we walked away,” Bellows says.

8. Know when to say no. That's probably the most important thing to do before you negotiate your first big sale. Have a BATANA (best alternative to a negotiated agreement) already lined up, and know just what you'll be willing to accept and what you won't. 

“Sanober took about three minutes to get me down below where I wanted to be on price because of some competitive products,” Bellows says.

But because he had the BATANA in mind, he knew exactly how far he was -- and wasn't -- willing to concede on price. In the end, Yesware agreed to a low price in exchange for a year's payment up front.

“It was a good deal all around,” Bellows says.

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