To cover one of your guys, shoot, or shoot close to an enemy. Then move a little closer, and shoot a little higher to the position where your enemy is. It's really easy, and it's kinda fun to watch the Nazis get scared.
In the second mission, "The Island", there will be an enemy under the second bridge with a FG42 scoped. That gun will get more ammunition every time you kill someone. After completing that mission you will have the gun on the third mission, but you must save the gun through the third mission to get it in the fourth mission and so on. It's a good way of killing your enemies, and you can get to high ground, or lay down to get a good sniping position. Check it out, and have fun.
To move your allies, use ADS and aim at them, then press Fire. Do not worry as you cannot shoot at an ally. Your ally should move from his location. This is useful when you are trying to enter an area blocked by an ally. Most of the time they don't get in the way, but sometimes they do, and it's annoying.
Successfully complete the game to unlock interviews with veterans Gordon Boulton, Sgt. John D. "Bud" Hawk, and Sgt. Stan Markut. I'm not so sure if they're alive now, but it's really interesting to listen to what they went through back in France. It's really something else. This tells you that the game might be fun,but it doesn't mean the war is fun. Trust me, it's not. Check out the interviews.
When playing in MultiPlayer games, if you find yourself having trouble hearing people, or it seems like people can't hear you, pause your game and go to the Headset menu. You'll see 2 options called Headset Volume and Headset Sensitivity (or something close to that). By raising the first one, other player's talking will be easier to hear. By raising the second, your microphone will pick up more sounds and send them to other players, meaning you don't have to scream in your microphone to make people hear you.