• Proactive attention: you are fully focused and prepared for your most important decisions/ most complex tasks.
• Active attention: you're plugged in, but also easily distracted.
• Inactive attention: you're likely to really struggle with complex or difficult tasks.

... based on your attention level.
Save difficult and important task for when your attention level is proactive, leave the intense but easier stuff for those active attention times, and try to save up the easy or dull stuff for when you're capable of little else.

• Make tiny changes to trick your brain and create additional periods of attention (for example, move to a different part of the room every hour).
• Keep moving and switch tasks every 30-60 minutes.
• Get outside and go for a quick walk.

• Take advantage of the periods when you're walking somewhere and make some phone calls. You can use your desk time for other tasks.
• Keep both a physical and a digital file of reading materials. Take advantage of the time spent commuting or in the waiting rooms for your doctor's appointments.
• Have a thinking list with big decisions for when you are driving or waiting in line for example.
• Instead of talking via email with your co-workers, invite them for a coffee.