NEW YORK (CNN/Money) – Once, entrepreneurial types swarmed to start Web sites. But three years after the dot.com crash, where does a go-getter go?

The real estate business.

Nearly 1 million people are now selling homes in the United States, according to a new National Association of Realtors survey, and the number is growing rapidly. Some 125,000 have joined the business in the past two years. More than 90 percent of the newbies left some other career to become agents.

Real estate may not be the kind of job little kids dream about. But astronaut or professional baseball player aren't viable career choices for most people. Besides, selling homes these days appears to be far more profitable than, say, becoming an actor.

So why not? Well, for one thing, it's hard.

Before you start making plans on how you'd spend your commissions, you've got to earn them.

"There's a perception that you run around looking at pretty houses and collect a check. That's the biggest myth," said Kate Kenny, who became a real estate agent two years ago and now works at Comey & Shepherd in Cincinnati. "Nothing is handed to you."

That's why so many try – then walk away.

According to estimates, nine out of 10 real estate agents leave the business within their first five years. Most often that's because it takes time to earn a decent living. As with any profession, those who stick it out the longest make the most.

The NAR says real estate agents with fewer than five years of experience typically made $35,400, before taxes, last year. Those with a minimum of 26 years selling homes grossed $67,500.

Years on the job isn't enough to get ahead, however. You also need sterling credentials.

"If you're known as honorable and hard working that will serve you in the long haul," said Ron Phipps, a real estate agent for 23 years who now owns Phipps Realty in Warwick, R.I.

He disagrees with those who say real estate is bulging at the seams with no room for newcomers. In fact, he encouraged his 23-year-old son to enter the profession.

But Phipps says new agents like his son need far more than a fat Rolodex of contacts to thrive. Friends may invite you to drinks, he warns, but they won't necessarily trust you to sell their home.

"You can make the contacts," insisted Phipps. "What it really takes is a good study of the demographics of the market you're working in and an analysis of the strategy that would be most effective to reach that demographic group."

Mentors also help.

Just ask Renae Wollter, who began selling residential real estate in the Atlanta area two years ago after getting laid off at a dot.com.

Since then, Wollter has sold about $1 million worth of properties. The studying she did to pass Georgia's real estate exam didn't prepare her for the day-to-day skills she needed after getting a job, such as negotiating over contract language.

"I can't imagine being in the industry and not having a mentor," she said. "You may be negotiating a $1 million house, and you have to make sure you're really careful. With each real estate transaction there's always something that comes up and there's a lot of stake. There are special stipulations when you're writing a contract for your client."

Wollter's own dad was a builder so she grew up around real estate agents. Like many of the uninitiated she, too, "thought they didn't do anything" to earn a living.

She's since learned her lesson. "It can be very draining. You have to be available for clients on weekends, weeknights. You always have to answer your phone," she observed.

"But the flip side is I love being my own boss. I'm not stuck behind a computer all day. I'm outside and I'm forced to network," Wollter said. "I like that. I'm sticking with it."