How to avoid low-level disruption.

Have a routine.

Having a routine in your classroom can help. For instance, plan to have a starter activity ready on the desks for the students every time they enter your classroom and as soon as they enter the room. They shouldn’t have any excuse that they “have nothing to do”.

Plan short and sharp activities 

Try providing students with a series of tasks that don’t take a long time to complete. This can help students feel that they are making progress and so keep them engaged.

Know your student's ability and differentiate accordingly.

The majority of students will start talking because they find the work too easy or too difficult. Each activity should have the same learning outcome, but there should be enough variety to suit all abilities. 

Move around.

 
Your presence is extremely powerful. Don't stay stagnant at the front of your class. Move around and don't allow the children to become distracted. Talk to them about their task. Give them deadlines. For example say: "I'd love to see two more ideas by the time I come back as your ideas are really interesting." Then walk and visit another child/pair but make sure you come back.

Identify where the transitions from one activity to another will be.

These are the times when students will talk. If a student genuinely doesn’t have anything to do because they are still waiting for the worksheets to be handed out, can you really expect them not to chat?