Driving teen-centric marketing: Teens' sway over buying decisions is rising. Nearly 68% of parents say that kids will influence at least half of back-to-school spending this year, up from 53% last year, the National Retail Federation says. NRF expects sales this year to top $54 billion, up 13% from $47.8 billion in 2005.

"Retailers understand that teens have their own money, and they aren't worried about gas prices and retirement plans," says the NRF's Ellen Davis.

"This is a group of consumers who has money to spend. When they find something they like, they'll spend money."

Trends in wooing teens:

• Be where they are. J.C. Penney (JCP) will be the sole retail sponsor for MTV's Aug. 31 Video Music Awards.

Ads on the show will cap a promotion that included a five-city mall tour with auditions for teens to be a correspondent on the show and ads on MTV websites and the network's other shows.

"MTV is where the kids are, and we've been building our back-to-school (advertising) to this crescendo," says Michael Cape, vice president of brand marketing.

A pair of ads on the show will have a novel "ad-within-the-show-within-the-ad" concept.

In one 30-second ad that will open a commercial break, a young guy prepares for a night out while live video from the show is playing on the TV in his room. A second commercial that will be the last in that break shows kids at a rooftop party watching the VMAs on a big-screen TV — again an insertion of live video.

That video fills the screen to end the ad and bring the viewer back to the show.

"We really wanted to challenge ourselves in blurring the line between show content and advertising. It's a way to keep attention levels high. If you don't keep up with teens, then you'll be left in the dust," Cape says.

• Have the right stuff. For a slice of the seasonal pie, office supply chain Staples (SPLS) added a teen-oriented mix to its supplies. "We marketed to teens," spokeswoman Deborah Hohler says. "You go about that very differently."

The inventory includes more colorful, hipper designs on items from calculators to CD cases.

Staples also put more products online and built a micro site — geared4school.com — where kids could enter to win a grand prize $10,000 Staples shopping spree.

• Go digital. Discounters Wal-Mart (WMT) and Target (TGT) made the Web central to teen marketing this year: Wal-Mart with a MySpace-inspired networking site, walmart.com/schoolyourway, and Target with target.com/backtoschool, where visitors can create characters.

"Media consumption for younger consumers is spent online," says Jon Swallen, TNS Media Intelligence senior vice president of research.