Though it's also tempting to just lump age segments together, it's a bad business move. "Now, microtargeting is the way to go," White says. "There are nuances between 14- and 16-year-olds." Just shoot something out to them instead of taking some time to figure out who they are and, well, they won't give your product a second look. This is especially important when talking to tweens: They're "an interesting crossover," says Stock. "They look up to older brothers, sisters, and friends, but they're not quite ready to cast off their own childhood."

One way to get all of the above going: Bring them into the process from the get-go. "Marketing starts with product development," says Marie Lena Tupot, research ­director of ScenarioDNA, which publishes the "Ignite! Youth" report. Adds Stock: Marketers should be about making products more customizable and thinking about getting kids involved in the product development.

Involve your target audience as you define the features set of a product, says White. Make sure it's really designed for them. Along with creating a better product, you'll get your audience excited and get a jump start on building word-of-mouth marketing.

But, for all their independence and desire to define their own personalities, it's also important to recognize that Millennial kids trust their parents - much more so than those parents trusted their own elders. Unlike the Baby Boomers or Generation X, Millennials want feedback from their folks about almost every purchase of more than a couple bucks. Back when Nickelodeon debuted in the 1980s, says Howe, the all-kids channel even had a parent-free zone. But Millennials want to see adults on the scene - parental characters don't just make cameos; they're integral to the shows. Take, for instance, The O.C. The Fox powerhouse ­drama features story lines about teens, about their parents, and about teens interacting with the parents - even taking advice from the parents. That influence cannot be ignored. "You have to gain the trust of the parents. Shopping decisions for teens and tweens are made in the context of the family," says Stock.