We go to an end zone and play a little chorale and get the sound focused. Play snippets of the show for memory sake. Kids pray at 1:00, then we march to the visitor's sideline. We play for the dance team first, so we enter the field the same way every week, and do the same at contest.
If we're performing second, we stand on the sideline (squared up on the 50 if the other band is marching off home, and to the 25 yd line if they're marching off visitor). They stand at parade rest with tuba and percussion off. They stay in formation, and watch the other band. Clap when appropriate.
It was pulling teeth to get my last band to do this. My current band bought in quickly. It's structured, and disciplined. I've seen other bands do other things, some successful some not.
Good luck to you!