Learn to yell with your diaphragm. Start with one command you know you'll be using the most like tench-hut, parade rest, etc. & keep at it until it comes easy. What helped me the most was belting the first syllable out like I got punched in the gut & had the wind knocked out of me. It's hard to explain, but you'll feel it when you get it right. source: me - USAF drill sergeant from 2015 to 2018