I joined the Army at 19, straight out of a grocery store job in California and completely clueless about military life. Looking back there is plenty I would have done differently, like focus on my military skills as much as I did on my MOS skills. When I deployed to Iraq and embedded with infantry units during combat operations I learned real fast that qualifying with my rifle did not prepare me for combat missions, but I managed by watching and copying what the guys did. Being a woman attached to all-male units also required a delicate balance of professionalism and friendliness, something the first women in combat arms units will soon learn.
Benjamin Franklin nailed it when he said, "Fatigue is the best pillow." True story, Benny. There's nothing like pushing your body so far past exhaustion that you'd willingly, even longingly, take a nap on a concrete slab.