I'm new to umpiring (HS and summer leagues) although I've played for 40+ years. What ONE piece of advice would you give me above everything else?

Timing, timing, timing! And above all else - timing!

If you cannot have fun, you will not enjoy umpiring.

Peace

Don't think that since you have experience in the sport, that you know the rules. I learned that real quick the first time i actually picked up a rulebook and read the whole thing.

I would agree that experience does not automatically make you a knowledgeable rules guy, but knowing the rules is not what umpiring is all about. You can be 100% correct on a rule and a coach will still challenge you and whether you got the call right. I have seen guys nail a rule and could not communicate what they saw and the coaches have a field day at the expense of that umpire. I would say about 95% of calls that get arguments are not based on rules, they are judgment calls.

Peace

Yes, good point J.

Thanks for the comments so far. I do know that I learned more about positioning in the half dozen games i've watched this spring trying to watch as an umpire than I can figure out from the NFHS book

Good umpiring mechanics is another area where your experience playing will not help much.

Except for one thing: when you slid into base just as the ball was arriving, you always knew where to look for the umpire, right? Now that you're working the game, be there!

Before you pick up bad habits from others and develop some of your own, go to a clinic or camp and learn the right way from the beginning. Jim Evans conducts week-end and one week clinics, Gerry Davis conducts various clinics, ABUA conducts clinics, etc.