When I first went to Afghanistan in the fall of 2007, the last thing I had on my mind was moviemaking. I was on a photographic assignment for Vanity Fair with my colleague, writer Sebastian Junger, in a remote corner of Afghanistan, close to the Pakistan border. Sebastian had decided it would be interesting to follow a platoon of U.S. soldiers over the course of their 15-month deployment and chose Battle Company of 173rd Airborne Combat Brigade, based in the remote Korengal Valley.

At the time, the news focus was still very much on Iraq, and despite what Hollywood thinks, there can be long, uneventful periods in war. So before we set off, I imagined I would have a pretty quiet assignment; we’d do a lot of walking through beautiful mountains, drink endless cups of tea with toothless village elders and occasionally get shot at. I was wrong.

By the end of October, 18 percent of all fighting in the entire country was taking place in the Korengal; 70 percent of U.S. bombs were being used there and Battle Company had sustained a casualty rate of around 25 percent killed or wounded.

Today, nearly three years later, our resultant film, Restrepo, will open in theaters on June 25th. It’s a visceral war movie that brings the viewer about as close as is humanly possible to what it’s like to be a soldier—and it’s all real.

Sebastian and I have been reporting from war zones for more than 10 years and making Restrepo is a distillation of all the things we’ve learned during that time—plus a lot we didn’t know, including a crash course in navigating the movie business (only slightly less dangerous than the actual filming).

You could say I’ve evolved a peculiar skill set in making documentary projects and images in extreme circumstances. Among other things, I’ve lived with a heavily armed rag-tag rebel army that pushed Liberian president Charles Taylor from power (events that formed part of the documentary Liberia: An Uncivil War), documented Janjaweed militia massacres on the Darfur/Chad border (footage of which was used in The Devil Came on Horseback) and even negotiated a hostage release from militants in the Niger Delta… by mistake.

Filming in Afghanistan had its own set of challenges. We lived high up on the side of a mountain in a small outpost that the men had built by hand and named ‘Restrepo’ after the platoon medic who had been killed early on in their deployment. There was no running water or electricity when we first arrived, no road up there and little chance of help if the place was overrun. We slept out in the open, surrounded by sandbags and ‘hesco’ rock bags; thick layers of dirt penetrated everything. Attacks on the outpost happened almost daily (one day we were attacked four times, which didn’t beat the record of 13). We basically did everything the soldiers did—except carry a weapon or pull guard duty—and the physical challenges of filming came in addition to the basics of long patrols on foot and being shot at. So, with this in mind, I’ve come up with my top 10 tips that may prove useful in case you decide to grab a camera and set off to make a war film:

1) First off, get fit. It seems an obvious one, but it’s hard to keep a camera steady if you’re out of breath.

2) Travel light. There’s nothing like getting a broken leg and having to walk down a mountain for five hours during a combat operation when you’re weighed down with a useless kit that you may have to throw away. Forget about a tripod; it’s a nice idea but totally impractical.

3) Don’t worry too much about which camera and lens to use (but try to avoid different formats). I always think that if what is happening in front of the camera is so incredible, then who cares what you shot it on. We used Sony Z1 cameras because we could smash them up and still afford to buy new ones without breaking the bank.

4) Avoid Improvised Explosive Devices. IEDs can kill you or really mess you up, but if you are in a Humvee, then try to keep the camera running in case you do get blown up and survive. Sebastian did while we were out there and that footage really makes you jump.

5) Keep your camera attached close to you with a carabina. It stops it from banging around when you run, means you won’t leave it behind somewhere if you have to dash, plus you’ll end up kicking yourself if a firefight kicks off and you can’t reach the place where you left it.

6) Wear a fanny pack with spare batteries, tapes, a spare XLR cable, sunglasses, sunscreen and an energy bar with you at all times. Soldiers may make fun of you, but it means that you’ll be okay if you end up somewhere remote. A satellite phone is a good idea, too, just in case you get lost behind enemy lines. I had a friend who managed to get separated from the unit he was covering in the Sunni “Triangle of Death”—not a good idea, but he survived.

7) Charge your batteries whenever you have the chance. We spent our time living at a small, 20-man outpost on the side of a mountain and often didn’t have access to electricity. We needed to know exactly how much power we had so that the cameras wouldn’t cut out at that crucial moment. Lots of interesting things happen in a war zone, but you need to get them on film, not just tell the story later in a bar.

8) Combat footage alone is not enough to sustain interest. After a while, war dogs telling stories by the bar can also be pretty dull. We spent a lot of time with the soldiers—nearly 10 months worth of filming in total—which meant we built up an unusual degree of intimacy with them that makes the moments out of combat just as interesting.

9) Carry a set of bungee cords with you. They’re useful if you need to stabilize the camera while you’re filming out the door of a moving helicopter. (Do make sure you’re strapped into your seat.)

10) Despite what Geraldo might suggest, I wouldn’t recommend carrying a weapon. Filming is more difficult if you’re confused about whether you should be fighting instead. I was offered hand grenades but turned them down on the basis that I wouldn’t want to get one mixed up in my fanny pack. MM

Tim Hetherington and Sebastian Junger’s Restrepo, winner of the Grand Jury Prize at Sundance, will open on June 25th.