1. Give the gospel every week in your main youth group gathering.
When you do this you are doing more than making sure every teenager in your youth group has an opportunity to hear and believe the gospel, you're also indirectly equipping teens to share their faith. When they hear you give it week after week then, over time, they will master the gospel and not even know how they did it.
2. Tell stories.
Relentlessly inspire your teenagers by telling stories of transformed lives as a result of the gospel of Jesus Christ. Tell both stories from the Bible, church history and teenagers down the street.
3. Let teens tell stories.
Have an open mike in youth group for teens to tell stories of other teenagers they are engaging with the gospel every week. Let them tell the good, the bad and the ugly. Spend time afterward praying for the teens who heard the gospel that week as a result of your teens evangelism efforts.
4. Make baptisms a big deal.
However you do it (sprinkle them, dunk them or send them down a slip-n-slide) do it. Baptism is a big deal. It is a public declaration of an inward transformation. When a teenager in your youth group puts their faith in Jesus and gets baptized make it a party of Biblical proportions. Have it match the party that happens in heaven every time a sinner repents (Luke 15:10.) Have them invite all their family and friends, especially the non Christian ones, and use this as an opportunity to spread the gospel some more!
5. Mobilize your teenagers for consistent evangelistic action.
To mobilize means to "inspire, equip and deploy a group for action." Have an evangelistic training program for your teenagers (Dare 2 Share can help with that by the way) that is consistent, practical, Biblical and relevant. And don't just train your teenagers take them out to share their faith consistently. This can be done through direct evangelism, social justice projects (where the gospel is given of course!), mission trips and, virtually, during every youth group outing.
Making evangelism a priority in your youth group is not as difficult as you may think. But it takes intentional, prayerful action. And when you start taking this action God will take action as well and your youth group will grow deeper and go wider as a result.
Go for it!