The weekend is a time for a change in rhythm, not just more of the same, thus Shabbat may not seem a special event. It's not just the teenagers that are the impediment, parents, teachers, friends, even our secular society is said to be at fault. School schedules recognize Sunday as the day of rest. If friends aren't Jewish or aren't observant, they don't recognize family claims on Friday evenings. Peer pressure means that if your friends don't go to services, you won't want to either.
Stores are always open.
Shabbat isn't inherent in that rhythm. Strategies Shabbat isn't just a list of actions to take, of things to do. First, a special mind set is needed, a way for adults to relate to teenagers. Allow your teenager to live in two civilizations. If you get them to services or to a family Shabbat dinner, don't worry if they wander off later in the evening to be with their friends.