First, grow out your hair and facial hair. Buy loose, baggy cargo pants and get them dirty. Get some neutral colored button-up shirts. Don't button them, but if you do, tuck it in. Get a nice wrist watch — analog! — and some nice brown boots. The last thing you'll need is a Nikon F3, or some film camera from the 70s.
Now onto the shoot. Approach your situation, outwardly timid, shocked, horrified, in awe, and alert, breathing through your mouth at a rapid pace and eyes darting. Run and duck behind dumpsters, jump over railings, get in the action and stay in the action while remembering to dart those eyes and keep raising your camera to your eye. It's important that you do this with degrees of anxiety and diligence.
Go out of your way for that action packed shot, the shot with the crazy diagonal lines and dust flying and terrified children looking straight into your camera, looking for help yet shocked and awed at your presence, a true war photographer, legs bent in a strong horse-stance — eyes darting, mouth wide open, breathing fast. Remember it. Think to yourself: "I'm a war photographer, and this is so intense, and I look and feel so intense, it's so intense and thrilling, I'm thrilled". Pinky up — just so, after you've finished the assignment and have your name across the headlines of all newspapers as the world's best photographer, you'll be lying in a hospital bed in agony with a missing pinky to remind everyone that YOU were the photographer that took those pictures on National Geographic's front page. And everyone will see you and think: if I could at least LOOK like this war photographer, I'd be a god damned warrior".
As you lie down in self-satisfied pain, begin to write an autobiography. Title it "Through the Lens of a Badass: An Autobiography", and make sure you sign it and then generously, heroically, give it to the first person you see on the streets of a country ravaged by famine and violence.