• The default mode network of our brain, responsible for mind-wandering and creativity, needs to be turned down when we want to work for any length of time.  
• The brain's dorsal attention network - the part that helps us make decisions and focus on a task - moves into action when we are deliberately focusing on a task.

When people are less able to focus for any length of time, they are leaning more heavily on the left hemisphere of their brain, while the right hemisphere is not working as hard as it should be working.

Brain training, using magnetic brain stimulation followed by computer-based training, may help a person to focus for longer.

Brain stimulation with a weak electromagnetic pulse can turn down the left hemisphere and force a person to develop the more efficient right hemisphere and boost the powers of concentration.

Your ability to pay attention is not about putting all your energy into the task - it's about allowing the brain to wander occasionally and gently refocussing.

When you get too stressed trying to focus, norepinephrine [a hormone responsible for vigilant concentration] receptors in the prefrontal cortex, shut off. It then makes trying to focus seem too hard and it makes us less able to concentrate.

Just like physical exercise, you have to keep training your brain to retain the benefits, or you’ll end up as before.

While research on brain training is still ongoing, mindfulness meditation may also help with continued focus. Another method to help you to focus is making a task more visually demanding. (It can be done by adding more colors or shapes to the page or increasing the number of sounds your brain has to process.)