Short and sweet:
Limit your time in front of glowing screens. And if you have to be in front of glowing screens—especially at night—use F.lux and low screen brightness levels. You’ll help your eyes, and make screen time more productive.
Read more. Read business books, biographies, fantasy novels, hard-boiled crime thrillers. Read how-to guides, political dramas, sports stories. Reading makes you think in ways that can help you break through creative blocks, discover new business ideas, and improve your mental acuity. (And if you’re an eBook person, like me, I can’t recommend ePaper highly enough.)
Be active. That doesn’t have to mean daily runs or workout sessions (bonus points if you do though… and I am intensely jealous of your dedication); getting outside to walk a few times a day is enough. It’ll give you an opportunity to observe the world around you, counteract all your sitting, and work through tough problems.