The spring home sales season is under way, and pros say this year you'll need every trick in the book to sell your house.

So take the mounted deer head off the wall, roll on a coat of cheery yellow paint and bring out the vanilla spray, say real estate agents.

With thousands of homes for sale, and thousands more waiting in the wings, 2007 is going to be more competitive than ever for sellers.

"Price it right and present it right, and hope you get lucky," says Yuba City, Calif., broker associate Doug Bryan.

But what does it mean to present a house right? What gives a house a "wow" factor? And what exactly is the "it" factor that makes a buyer say, "This is the one"?

For sellers, those questions may be the difference between selling a home in four days or four months.

Real estate agents claim to know precisely what pleases or repels people when it comes to the biggest financial transaction that many will ever make.

It's not rocket science, they say. Certain colors stir certain emotions (yellow supposedly says "buy"), and certain smells (fresh-baked cookies) take buyers back to childhood.

In a trade where most potential buyers supposedly decide within 20 seconds if your house is a go or a no, agents say subtle tactics can give a house an advantage over its competitors.

Rule one for sellers is much like the doctors' code: "Do no harm." Agents advise doing nothing to distract buyers.

No cat box in the laundry room. No sexy glamour shots in the bedroom. No cobwebs in the corners, no dust on the ceiling fan.

"You want to take away your personal stuff," says Sacramento, Calif., real estate agent Patrick Lieuw.

That means no stuffed elk heads on the living room wall.

"If people like to hunt, they put up a trophy," Lieuw says. "If you happen to find a hunter, they love it; but someone from the Sierra Club, it turns them off."

Family photos? Lose them. Buyers want to envision themselves in the house, not the owner and especially not all the owner's furniture, household clutter and children's baby pictures.

"Put away all the photos that hang up on the wall. [They] will distract the buyer," Lieuw says. "If you believe you're really going to move, why not start to pack? Less clutter makes your house look bigger."

Finally, no all-white interiors, says Elk Grove agent Tracey Saizan, 2007 president of the Sacramento Association of Realtors.

"White is sterile. It has no personality," she says.

When it comes to painting, the simplest application may be just doing the exterior trim, say some agents.