Here's my take. I was MD at Fredericksburg for the last 2 years.
First thing is safety. Its your job to account for each and every round that leaves a competitors' gun. Course design need not be dangerous to be challenging.
Next, you have a monumental job. Get lots of help. Don't do more than you can manage...if folks won't volunteer to help, you will just have to have a less than satisfactory match -- We had a big match. Over 100 competitors per month, plus Area 8 and Va/ MD section. It takes a bunch of folks to get that much work done. Stats, Registration, Course Design, stage building, etc... We put 7 stages on the ground every month and it took an experienced crew of 8 to get it done, especially in the summer heat. As a rule, if you help, you shoot for free. There will be those who help a lot. Be accommodating of those folks... they're your greatest asset and will make you look good.
I enjoyed being MD, but my shooting suffered terribly. I was the first at the range and the last to leave. I rarely put a gun on before make ready on my first stage and was always done before the last shot was fired.
Mostly its a great opportunity to get to know a lot of good people. Enjoy their company and learn from them. There's a lot of interesting people in USPSA.