[g2e]

A few things are important in my opinion regarding productivity:

1) Minimal lying in bed. If you're in your bed, you should be sleeping. If you can't fall asleep find out why and fix it.

2) Don't get distracted. Of course, easier said than done but you can definitely minimize any possibilites.

3) Experimentation with sleep. Try sleeping a little bit less and less until you find the minimal amount required for you to be refreshed.

4) Continuously reflect and ask yourself if there's a better or more efficient way of doing something.