According to a study by the Small Business Administration, nearly 70% of U.S. sole proprietorship companies earned just $25,000 in 2010.  If you're among that group, you are likely missing out on one of the most lucrative opportunities available to small businesses: selling to corporate America.

Angelique Rewers, CEO of the The Corporate Agent, says that big companies spend big money with small business. That's right; every year corporations in the United States spend more than $2 trillion buying services and products from other companies. And now more than ever before, these corporations are actively seeking out opportunities to work with small business owners. Powerhouses such as Wal-Mart, Chevron, IBM, and Macy's have launched major programs to buy more from small companies, giving those owners a window of opportunity to grow their businesses by selling in the corporate marketplace.

Rewers, who helps her clients tap into the trillion-dollar market of global corporations, says that, according to the Women's Business Economic National Council, within two years of adding the first corporate client to their small business, women entrepreneurs experience an average increase in revenue of 266.4%. Presumably it's about the same for male entrepreneurs.

"And money isn't the only benefit," says Rewers. "Working with marquee clients can also bring added credibility and visibility that can lead to bigger and better things. For the small business owner trying to make a difference in the world, bigger clients can also translate into a bigger positive impact."

But sometimes cracking the code to this $8.73 trillion marketplace can be daunting. Here are Rewers's five surprising tips to make selling to corporate clients a little easier.

1. Take the road less traveled.

Sometimes the best door into a corporate client is the one that no one else considers. Pretend for a moment that you're a health and wellness expert, and you'd like to sell your services to a large company. Who at the company would you contact?

Common sense might say the human resources department. But guess what? A hundred other wellness experts are thinking the very same thing.

In this scenario, the road less traveled might lead you to the head of the company's customer service department. Research shows that happy, healthy employees treat customers better. This leads to as much as an 85% increase in corporate profitability. This customer service director may be quite happy to hear from you.

The bottom line here is that decision-makers exist all throughout corporations. Find the more creative points of entry and you can often rise above the noise.

2. Timing is everything.

The biggest obstacle to selling to corporate clients today is that people on the inside aren't just busy, they're frenzied. Small-business owners who are highly successful in landing corporate clients not only understand this, but they also do something very smart: They time their sales pitches to match up with what corporate decision makers are preoccupied with at that very moment in time.

Staying in the know is a lot easier than it may seem. By setting up Google alerts you can keep an eye on relevant press releases and news articles about your target clients. As a result, your pitches will be more targeted and timely, and you're much more likely to get a response.

3. Don't try to sell them anything.

It sounds counterproductive, but not trying to sell a company on your services immediately can sometimes lead to a sale more quickly than a hard-nosed sales pitch.

Here's how it can work. You see a news report about a company in a situation that you are well equipped to help with. You call the head of the affected department, mention that you saw the news coverage and offer to e-mail over a resource that might be helpful to them. Without trying to schedule an appointment, talk about your services, or make a sale, you end the call.

On the other end of the phone is a bewildered albeit happy corporate decision-maker who now views you as a problem solver, not as a pushy salesperson. This puts dividends in the bank for the next time you reach out.

4. Approach sales conversations like a toddler would.

Parents will attest to the fact that a toddler's favorite question is, "Why?" It's never just one solitary, "Why?" It's a long series of "whys" until mom or dad runs out of ways to respond.

Little did we know it back then, but as kids, we were practicing one of the most effective approaches to help clients understand their needs. Drilling down by asking your prospects, "Why?" will identify where you can add the most value. Even better, you're positioning yourself as a trusted, strategic partner before they client has hired you.

5. Don't try to be a mind reader.

An amazing transformation often happens when small-business owners reach the point when it's time to close the deal. Driven by fear, they suddenly they go from being a charasmatic and open to being bashful, and trying to be a mind reader rather than discussing precise terms of the deal.

But to get deals closed quickly, you need to roll up your sleeves, get specific with clients and, above all, not shy away from talking about their investment amount. Addressing the money issue early in the conversation will bring fewer surprises later, which is better for both you and the client.

This is the tip of the iceberg. Rewers was on my Internet radio show last week and gave away a wealth of information. Tune in if you want the gritty details!