I use numbered heads together often. This strategy is good for reviewing for a test or quiz.
Think, Pair & Share Activity is also a good strategy for teaching middle school students.
The activity gives the students an opportunity to think about a question. After thinking they can write comments or answers and pair with students with the same interest. Later, students can share their findings with the class, parents, and even other teachers. This activity can help students who are shy and have low self esteem overcome their fears. Both of these strategies work for me.