Take Care Of Yourself
Important and Sometimes Overlooked Productivity Tip: Keep yourself in good health!
Eat a varied and balanced diet. Move around. Do something that raises the heart rate for at least ten consecutive minutes a day; I felt a bit disgusted when I realized I wasn't even doing that. Get fresh air and sunlight! And SLEEP. It's easy to forget how much more alert the mind can be when it gets regular, proper rest. Find a sleep schedule that works for you, whether you like to rise early or late, and try to keep it consistent.
It's easy to get caught up in creating, but don't neglect yourself! Take your food and bathroom breaks, stretch, breath, and give your eyeballs some rest by moving them around and gazing off into the distance.
It's simple stuff, but fundamental. Everything is better and easier when you're energetic and alert - why subject yourself to the potential heartbreak of careless mistakes?
(This post is definitely made in the "AA" spirit of the blog - I'm trying to change my own poor habits!)