1. Go on a prayer walk for 30 minutes every week. Spend time interceding on behalf of every teen in your group and revival on every school they represent.
2. Take time in your actual meeting for intercessory prayer. Cut a song or game or two and add in a time where teens can pray in triplets with and for each other. Spend time praying specifically for classmates who don't know Jesus.
3. Do a series on intercessory prayer and use it as a launching point for prayer as a priority in your youth ministry.
4. Lead a weekend retreat centered on prayer. Teach lessons on it, talk about it and, most of all, do it! Teach them how to do prayer walks (hikes), write their prayers to God, prayers aloud all together, prayers in silence, etc.
5. Meet with your core student and adult leaders weekly 30 minutes before students start to arrive in youth group to saturate that night in prayer.
6. Read a good book on prayer. (Prayer by Phillip Yancey, The Ministry of Intercession by Andrew Murray, The Weapon of Prayer by E.M. Bounds, etc.)
7. Have a "Prayer Party" where teens can invite their friends to be prayed with, for and over (and of course share the gospel with them too!)
8. Recruit a group of adults in your church (Sunday school class, small group, etc) to intercede on behalf of your youth group.
9. Get in touch with a Moms in Prayer group in your area and brainstorm ways of praying for the teenagers of your community.
10. Scrap the lesson this week and just pray!