Once some people complete their to-do list, they add more work. This is a dangerous move that can sabotage your productivity.
Sources of open loops:

• Studying. Do you have a specific list of learning activities, or do you just...

• You’re busy: separate 5-15 minutes to write, first thing in the morning, and stick to it.
• You’re intimidated: The important thing is to start.
• You’re not motivated: Commit to writing to an accountability group and report to them if you wrote or not.

In the afternoons distractions have the most power:

• Move your body at the same time every day so your brain knows you’re still getting stuff done.
• Save the easy stuff for the afternoon when you can switch on autopilot.
• Spend just 5 minutes on that “Big Thing”, but only ...