As someone who also had a longish path to learning to work hard, the answer for me was simple: practice. Gains in focus time (for me, anyway) are incremental,

As someone who also had a longish path to learning to work hard, the answer for me was simple: practice. Gains in focus time (for me, anyway) are incremental, so it’s not like you wake up one day and can focus for 12 hours straight. Accept that it will be a slow road, and just keep trying to stay focused longer, whenever you sit down to work.