Knowing as much as possible about your preteen students can be a big help in improving your teaching effectiveness. First of all, it's important that you know the physical, mental, social, emotional, and spiritual characteristics of the age group with which you work. Knowing these facts—why kids act the way they do—can affect how, why, and what you teach. Meet with your coworkers to study these age-level characteristics.
Then accept kids where they are. Accept them because of who they are, and respect them! There's no room for "favorites" if you want to reach all the kids in your group. Every preteen has something special about himself and something unique to offer. Find out what it is, and get busy helping that young person feel special and wanted.
All-Stars for Jesus Bible Clubs are expressional training programs designed to involve kids and let them learn by doing. So don't always do things for them. You as the teacher should always be available and ready to help, if needed, but you should sometimes be in the background. Instead of finding the answer for them, show them where they can find it for themselves.
When your students get restless, you as the leader always need to ask "why?" Usually it's because (1) the activity is too long for the attention span of the group or (2) the activity itself is boring. If this is the case, it's your responsibility as the teacher to correct the situation. Change the activity and always have a variety of activities up your sleeve in case one doesn't work out or is over faster than you anticipated. Again, be prepared. Your preteens will seldom grow bored or restless if there's a fast-moving, variety-filled program or lesson in which they are actively involved.
Youngsters, even preteens, are looking for role models. You have a unique opportunity and responsibility as a preteen Bible teacher to be the kind of positive, Christian example they need!