Practice marching with the right posture. Straighten back, stretch upwards, lean forward slightly, bend your knees very little without locking your knees. Try to walk from heel toe. Put fee at a certain angle and make it a bit like you're rolling forward from heel to toe.
Something like that. We had to practice posture, standing, marching to the beat, reaching points using exactly the right timing and the exact amount of steps (8 steps for a bar or something). Learn how to judge step size and distance to choose the right step size so you get the timing right and be synchronized, etc.
Oh and learn how to play while marching to the beat without fucking up. So it'll still sound nice as you're marching. Oh, and we had fucking plumes, so people can see the angle of your head pretty well sometimes.
Put these videos below at 2x speed if you don't want to spend too much time watching marching videos.
Here's a link to some of the stuff competitive high school bands did.Here's a college level one I found Aggie's are known for their precision so I thought that'd be pretty cool to show. It got mentioned once by some band members.Here's another Aggie oneThis one came up for most beautiful marching band sooo. Definitely watch this one.It's not as precise, but it's pretty interesting and flashy.
Daaammnn aggie stuff is pretty damn cool to watch. Sheeesh, how much practice dangit? Those formations are so tight and precise. How do they not smack into each other. The second aggie video is more impressive I think.