I hold the shirt facing front away from me, left arm in left hand, middle of the collar in right hand. fold all the way down the middle, from the top of the collar (right hand) and grab the right arm with your left hand so you're now holding both sleeves in the left hand, closer to you than the right hand. make it all neat so the creases are where you need the, epaulette holders lined up etc, then i hold the shirt against my torso with the right hand, and fold both sleeves diagonally down, away from me, so they're just about touching the other side of the shirt, then fold the whole lot in half, so the collar is touching the bottom of the shirt. nice rectangle shape, goes at the bottom of my hard-shell suitcase and isn't creased when i take it out in a few days time to wear on the return sector!
That or I don't iron it and i wear a nice cosy jumper....! God i love winter