Psychology Today asked 15 experts how to be productive. You can read the whole explanation here, but these are the tips:

• Take breaks from your desk to stimulate your productivity
  
• Don’t be afraid to close your door.
• The George Washington Method. (I didn’t know this one: Washington, a farmer, always carried a portable sundial with him. His method entails picking an arbitrary point deemed ‘Noon’ and moving forward in segments from there, keeping your focus only in the ‘hour’ in which you are working. The White House cleaning staff still use this method today.)
• Stress relief helps reduce distractibility.
• Buck conventional wisdom if something else works better for you.
• The Pomodoro Technique (25 minutes work, 5 minutes break)
• Work until you complete one chunk.
• Make a plan to deal with unresolved issues to free up your cognitive resources.
• Make a shitty first draft
• Use conditioning techniques.
• Use an app to cut yourself off from the internet.
• Small blocks of time.
• Put your phone away when you really need to get something done.
• Don’t overestimate how much you can get done in your available time.