There's an old saying in teaching for classroom management: "Get them in, get them on-side, get them out". Getting them in, and out may be considered easy, and are often overlooked for perfect opportunities to enforce your behaviour management techniques. If they enter your classroom like a messy rabble, take them back outside the classroom, explain how to enter a classroom and how to sit down, and then send them in, standing by the door on the inside, inspecting each one. Repeat until you're happy. The same for the end of the class. The classroom is not to be left in a messy state (you of course will plan tidy-up time for practical subjects), and is a great opportinty to enforce who's in charge as it were, dismiss the class, either by table, row, or some other grouping. When you feel comfortable with the class, allow them to go all at once.

Resources

If you have access to an overhead projector, it really offers you almost limitless ideas to help grab, and hold the attention of your class. One such technique we use is at the beginning, and sometimes end of the class. We'd use this interactive clock as a starter. Either jumbling up keywords for the topic and making a game out of it - split the class up into two groups, and keep score. We quickly discovered the class is eager to get in as soon as possible, and all sit attentively waiting to start! This is the perfect time to 'rehearse' your classroom management rules. If anyone from the team shouts out, they lose a point (quickly explain why this is bad), if they help someone next to them, they get a point (again, explain why this is good) etc. If someone from the 'team' doesn't sit down properly or is loud at the start of the class, deduct so many points. This really brings out the competitve nature in boys, and helps to get them on your side.