A couple of years ago Chap Clark made the following comment at a gathering of middle school youth workers:
"In ministry to young teens, the feel of the ministry is more important than the content."
That comment launched us into a discussion around the idea that creating a ministry that feels safe, accepting, comforting, etc. is actually more important than the content you teach because of the crazy place young teens are at developmentally.
I think I agree with Chap. That isn't to say biblical instruction, learning doctrine etc. don't play a part in junior high ministry; they do. It is to say, however, that how a ministry feels to a young teen is equally important (so maybe I don't agree that it's 'more important', but that it is equally important). Creating positive memories, building relationships, creating a safe place to ask questions and share doubts, providing lots of experiential learning, surrounding students with caring adults etc. are crucial pieces of an effective junior high ministry.
If we can create an atmosphere in our ministry that is comfortable to junior highers during the 2-3 toughest years of their lives, we'll probably keep them around for years to come which will provide plenty of time for deeper content.