일단 문제는 You want to attract more teenagers to your store로했고

문제해결은 How about distributing flyers in hot spot such as in front of subway station or on the main street. Then You can easily get attention from teenagers.
I think it's a good idea to make online advertisement and you should post your website. These days many teenagers always carry their smart phone. Therefore they can easily access the internet anywhere at anytime, so they can easily see your online advertisement라고 했는데 괜찮을까요? 문제점에서 store가아닌데 store라고 했으니 이건 점수깎이겠죠>?ㅠㅠ