Step back and look into your company from a fresh perspective

You grind along day after day, trying to make your start-up a success.  You already know you're doing everything you can, because you're "heads-down" 24/7.  But sometimes we get so caught up in the day-to-day tactical stuff, that we miss grand opportunities to step back and take a new perspective.  Some of my best insights in whatever start-up I happened to be involved in at the time, were when I was stuck on a plane or somewhere with no email and minimal distractions, and I was forced to be idle.  That's a golden opportunity to step back, and "re-view" how you've been approaching the challenges of the company, whether they are technical or business-related.  That's when new insights into how to approach a technical problem, or new ideas of how to attract that first customer, etc., come about.  (This, by the way, is effective in any job and any career, even flipping hamburgers.)  Another way to accomplish this is to find a consultant who has domain knowledge in your space, and bring him in for a design review, or a business review.  A well-respected person from the outside can bring new insights and ideas to your company.