Yes, I know about being one! If you have heard of George Parks/Drum Major Academy, I work with him over the summer in Illinois where there are 600 drum majors on the field we are training at once! It is QUITE insane! The main piece of advice I can give is hopefully you won't be a drum major; you will be a role model. When you a drum major, you are a commander in chief, you're a secretary, you're a doctor, you're a peer mediator, you're a teacher, you're a listener, and most of all, you're a friend. You hear this jibberish about how people will look up to you....it is MORE than true! Your pride, your integrity, dignity, whatever you want to call it, is what you do off the field as well. If you have upcoming freshman who love the marching band and what they are doing, they will watch every move you make, whether it is during rehearsal, going to class, or in the mall! The feed off of your energy, your reactions. NEVER wear your emotions on your sleeve if it's a bad situation. And I'm sure you know what it's like to march, so be one of them! And if you get anything, LEAD BY EXAMPLE! If you act tired, they'll feel tired...if you cut up, they'll start talking...if you stay on top of things and know what is going on at every given second, hopefully they will take that initiative as well!
As far as commands go, etc. good luck! Every program is different, but it's always the fun part! The other thing is, in your conducting, be MUSICAL! It's what you love, show it! Have expression, just don't keep time!
I hope this isn't totally off the wall, or to insightful or anything, but these are just a few of the things I have learned in years past. If anything with this, have fun! It will be one of the most rewarding experiences of your life! Best of luck with your season, and you will have to be sure and keep us all updated as the summer/fall progresses!! God Bless!!!!