My youngest is gone -- moved clean across the country and going to college in Vancouver, working and her boyfriend takes up any free time left. However, while she was here, I learned something about teenagers. Your post hit the nail on the head. They love eating out, they love clothes, and if you've got a girl, they love make-up. And then of course there is iTunes and YouTube.
The kids are very social, and they are more apt to buy from vendors who engage them online. I see a lot of businesses that don't do social. They spend a few hundred thousands on a storefront and $500 on a website that does nothing for them.
I wrote an article about this today, although it isn't about teens. If you're interested, you can read it here: http://stevemaclellan.com/plug-in-your-business/
A quote from the article says:
"Years ago I built a website that sold advertising to local used car dealers. We’d drive around and visit with them on a regular basis and even stop in on the ones who said they weren’t interested in advertising with us. To some, that may seem like a waste of time, but it wasn’t. People like to do business with people they know and like, and building relationships is the way to do it. After a while, some of these other dealers decided maybe they would advertise with us. Today building relationships can be done through social media. Many companies are completely ignoring this method at their own peril."
So from my experience with teens, if you want to market to them, you need to have a good website that connects them with your Facebook page, Twitter, YouTube (many teens have YouTube accounts and subscribe to channels and share the videos with their friends) Pinterest, and Instagram -- without forgetting the old standby -- email marketing.
And websites need to be responsive. There is a good chance that teens will be viewing your website on tablets or smart phones and placing orders while "on the go".
Things have changed and teenagers don't use the yellow pages. For that matter of fact, few people under fifty, use the yellow pages any more.