I appreciate the tips Isaac, this fall is going to be my first time playing high school football, and I'm hoping to be the starting punter. Thank you so much!
Just a thought since you discussed walking straight. Would it help to get a cheap 25' tape measure (8 1/3 yards so you won't trip over the tape housing)... put the tip into the ground and lock it out at 25'... and use that as a middle for your feet and you can see if you walked one way or another during the punt?
That's a good option, what I usually tell guys is cones so that way it forces them straighter or use one of the pre drawn lines on the football field, but a tape measure or a towel are also good options.