90-minute exam revision session with distant thunder and a timer, when you are cold and want to be warm

1 Before you start

• Write down the one thing you are going to do, in a single sentence, before you start.
• Tell yourself the goal is time spent, not output produced.
• Put the thing you keep reaching for out of arm's reach.
• Decide what you will do if you get stuck: write the problem out, then move on.
• Make sure your chair is at a height where your feet are flat on the floor.

2 While the timer runs

• Notice the moment your hand moves toward your phone. That moment is the whole skill.
• When you notice you have drifted, do not restart the block. Just come back and carry on counting from where the timer is.
• When you have drifted for the fifth time, that is still four returns. Keep going.
• If you feel the urge to check something, write it on the paper beside you and keep going. Deal with the list afterwards.

3 When it ends

• Leave the desk tidier than you found it. Two minutes now saves ten later.
• Decide whether the next block is the same task or a different one. Do not drift into it.
• Put the notes you made where you will find them next time.

4What to put on

distant thunder — Low rumbles with long gaps. Suits people who find sudden noises more distracting than constant ones.