L4D (both): Practice using the sniper rifles. They can shoot clean through infected, so they're even better than assault rifles for clearing a narrow corridor, and they chew up Special Infected. However, NEVER take a sniper rifle if everyone else is already using one - one sniper, MAYBE two, is more than enough, any more and you'll be roflpwned hard.
Men of War, first mission: Direct Control (END key) the KV-1, and leave your infantry behind. There are few things more satisfying than rampaging through a village, hunting Germans. Also, you can drive through buildings, and use HE shells against anything that isn't a vehicle, such as infantry, walls, buildings and big brown explodey fuel tanks. Also, when you're aiming at a more distant target, WATCH FOR INFANTRY! I've lost that mission so many times because some brave, courageous soldier ran straight up at my tank and tossed an AT grenade.
Red Orchestra: You can fire the MG34 and DP-28 from the hip if you press the ironsights key. You'll move slowly and you'll have wicked recoil, but remember: SMG = pistol-calibre round, LMG = rifle-calibre round. You'll need several direct SMG hits to bring someone down, but only one LMG shot. I've won numerous duels this way. (And, with some practice, you can aim pretty well even at longer distances.)
Also Red Orchestra: When using the MG42, short controlled bursts are your friend. Keep holding down the trigger and you'll run out of ammo fast, and barrel change about doubles the reload time. The MG34 and DP-28 don't suffer from this problem as much because of lower mag size and RoF. Also, while it's hard to actually overheat the DP-28 (IIRC, it takes almost all your ammo, firing constantly), the low magazine capacity means you'll need to control your fire anyway, or you're gonna be staring down the barrel of a Kar98k or MP40 while you're still leisurely grabbing a new drum.
Still Red Orchestra: Learn to aim from the hip! It's fairly easy with SMGs, but if you can hip-fire accurately with a rifle, you've got a much better chance at winning indoor duels, especially if you get the drop on the enemy. I once killed two Germans at close quarters with a Mosin-Nagant from the hip.
Keeping with the theme: When you have the opportunity, ALWAYS rest your weapon! Windowsills, low walls and sandbags allow you to rest your weapon in ironsight mode, dramatically reducing your recoil and idle sway. Also, when weapon rested, ALWAYS go prone to reload and pop back up to fire.
Red Orchestra, this time with tanks: Don't hog the tanks! Most people do, and it works, but you'll be much better off with at least a two-man crew of driver and commander/gunner, using vehicle voice chat, especially if you've practiced playing together. You'll be much more manoeuvreable, since you only need to stop to aim and fire. Especially useful with tanks like the Tiger and IS-2, which possess tremendous firepower but have long reload times.
Again: Download Darkest Hour and practice, alone, on the Firing Range map. It's a shame a thing like this wasn't included in the original game, or in any other game for that matter.
C&C Generals (and Zero Hour): If you're playing against the USA, don't just build a superweapon as soon as you've got the requisite $5000 - Auroras die easily, but they make terriffic superweapon assassins. Try to destroy the enemy Airfield(s) first.
Mass Effect 2: The Mantis and Widow may be extremely powerful, and easily capable of one-hit kills, but a properly-wielded Viper can bring down two or three weaker enemies (like vorcha) in the time it takes the bolt-action rifles to kill one and reload. Choose your weapon accordingly; if you're gonna face large numbers of enemies (like on Omega or the disabled Collector ship), use the Viper (if you have it); if you're gonna face smaller numbers of more powerful enemies, use the bolt-actions.
Again: The Revenant is a massive powerhouse, but inaccurate like nothing else. Don't hold down the trigger at anything beyond about 2m (or large targets like gunships, where most shots will still hit if you aim correctly). Instead, pulse your fire to maintain at least some semblance of accuracy. And don't even think about using it without the accuracy upgrade.
CoD4: If you're in a large game on Broadcast, try to get to the small chamber overlooking the computer room. You'll be an attractive target, and your life expectancy is low, but if the enemy doesn't know you're there yet you can rack up the kills. Also, taking claymores and planting them covering the entrances helps.
CoD4: If you're in a large game on Creek, plant claymores in the small tunnel. If you put them behind rocks or something, it's impossible to notice them, and - barring death or grenades - they WILL explode.
CoD4: On Pipeline, especially in larger games, claymores in the tunnels are your friend. Also shotguns.
MW2: Enemy UAVs and counter-UAVs are susceptible to anti-aircraft missiles. Enemy UAV scrambling getting you down? Fire a Stinger at that mofo.
Men of War, first mission: Direct Control (END key) the KV-1, and leave your infantry behind. There are few things more satisfying than rampaging through a village, hunting Germans. Also, you can drive through buildings, and use HE shells against anything that isn't a vehicle, such as infantry, walls, buildings and big brown explodey fuel tanks. Also, when you're aiming at a more distant target, WATCH FOR INFANTRY! I've lost that mission so many times because some brave, courageous soldier ran straight up at my tank and tossed an AT grenade.
Red Orchestra: You can fire the MG34 and DP-28 from the hip if you press the ironsights key. You'll move slowly and you'll have wicked recoil, but remember: SMG = pistol-calibre round, LMG = rifle-calibre round. You'll need several direct SMG hits to bring someone down, but only one LMG shot. I've won numerous duels this way. (And, with some practice, you can aim pretty well even at longer distances.)
Also Red Orchestra: When using the MG42, short controlled bursts are your friend. Keep holding down the trigger and you'll run out of ammo fast, and barrel change about doubles the reload time. The MG34 and DP-28 don't suffer from this problem as much because of lower mag size and RoF. Also, while it's hard to actually overheat the DP-28 (IIRC, it takes almost all your ammo, firing constantly), the low magazine capacity means you'll need to control your fire anyway, or you're gonna be staring down the barrel of a Kar98k or MP40 while you're still leisurely grabbing a new drum.
Still Red Orchestra: Learn to aim from the hip! It's fairly easy with SMGs, but if you can hip-fire accurately with a rifle, you've got a much better chance at winning indoor duels, especially if you get the drop on the enemy. I once killed two Germans at close quarters with a Mosin-Nagant from the hip.
Keeping with the theme: When you have the opportunity, ALWAYS rest your weapon! Windowsills, low walls and sandbags allow you to rest your weapon in ironsight mode, dramatically reducing your recoil and idle sway. Also, when weapon rested, ALWAYS go prone to reload and pop back up to fire.
Red Orchestra, this time with tanks: Don't hog the tanks! Most people do, and it works, but you'll be much better off with at least a two-man crew of driver and commander/gunner, using vehicle voice chat, especially if you've practiced playing together. You'll be much more manoeuvreable, since you only need to stop to aim and fire. Especially useful with tanks like the Tiger and IS-2, which possess tremendous firepower but have long reload times.
Again: Download Darkest Hour and practice, alone, on the Firing Range map. It's a shame a thing like this wasn't included in the original game, or in any other game for that matter.
C&C Generals (and Zero Hour): If you're playing against the USA, don't just build a superweapon as soon as you've got the requisite $5000 - Auroras die easily, but they make terriffic superweapon assassins. Try to destroy the enemy Airfield(s) first.
Mass Effect 2: The Mantis and Widow may be extremely powerful, and easily capable of one-hit kills, but a properly-wielded Viper can bring down two or three weaker enemies (like vorcha) in the time it takes the bolt-action rifles to kill one and reload. Choose your weapon accordingly; if you're gonna face large numbers of enemies (like on Omega or the disabled Collector ship), use the Viper (if you have it); if you're gonna face smaller numbers of more powerful enemies, use the bolt-actions.
Again: The Revenant is a massive powerhouse, but inaccurate like nothing else. Don't hold down the trigger at anything beyond about 2m (or large targets like gunships, where most shots will still hit if you aim correctly). Instead, pulse your fire to maintain at least some semblance of accuracy. And don't even think about using it without the accuracy upgrade.
CoD4: If you're in a large game on Broadcast, try to get to the small chamber overlooking the computer room. You'll be an attractive target, and your life expectancy is low, but if the enemy doesn't know you're there yet you can rack up the kills. Also, taking claymores and planting them covering the entrances helps.
CoD4: If you're in a large game on Creek, plant claymores in the small tunnel. If you put them behind rocks or something, it's impossible to notice them, and - barring death or grenades - they WILL explode.
CoD4: On Pipeline, especially in larger games, claymores in the tunnels are your friend. Also shotguns.
MW2: Enemy UAVs and counter-UAVs are susceptible to anti-aircraft missiles. Enemy UAV scrambling getting you down? Fire a Stinger at that mofo.
