Haven't been a CEO, yet, but I have worked a high stress job that involved a lot of team coordination/leading and these were my takeaways:
Short Term:
1) If you have other business to attend to today--i.e. the customer--get out of the office for an hour and go take a walk or read a book somewhere quiet and private. Driving yourself batty waiting on everyone else is a fool's errand.
2) If nothing is going to be done "today", call it a day and go home. Seriously. Use the time to run personal errands, think, and do things that will take your mind off of the things holding you up.
A former CEO would get real fidgety when things weren't done exactly when he envisioned them and would then spend the next several hours frequently checking in with us and just slow things down. If you're getting antsy about things, the best thing you can do is take yourself out of the environment until you calm down and not infect the rest of your team. People feed off their leader's emotions and if you're getting fidgety they'll start getting nervous and frustrated.
Long Term:
1) Budget in time for self-improvement. Be reading as much as you can, take up a physically active hobby that gets you moving, and try to improve in areas of weakness.
2) Budget work time to think and plan out the business. Bill Gates was famous for taking thinking trips where he'd duck out for a week with a stack of research papers and other materials to see where the industry was headed and figure out how to get in front of it. You might have not the time to take a week, but take a day here and there to pay attention to the trends going on around you.
3) Know when to hold 'em and know when to fold 'em. Sometimes you gotta ride herd when things aren't getting done for legitimate reasons (i.e. everyone's clowning around). Other times, you gotta let things ride and accept that it's not all under your control -- you can't control the server crashing, unforeseen technical bugs, delayed client responses etc. Learn to be comfortable with things not being under your control and not letting it frustrate you to no end.
4) Enjoy the down time! Really. We all think we have to be hyper productive all the time and any down time is simply a waste of our time because we could be doing something. I struggle with this a lot and it makes it hard to be. Consider having an unplanned hole in the schedule as an opportunity to take 15 minutes to clear your head--writing helps me a lot--refocus and prepare for the next challenge. Those unplanned holes can be a lifesaver if you count them as a blessing instead of a cost.
Edit: Grammar errors.