Instructions
Create weapon classes that are versatile for different maps and stages. For smaller maps, creating a sniper rifle class will not be beneficial because there are not many places to hide where it is safe to snipe. Using automatic weapons in small maps will increase your KD ratio since you will be able to aim down faster and shoot more rapidly. Medium- and large-size maps can support any type of weapon.
Stay close to buildings and obstructions and never walk out into an open area. Walls and other debris act as a shield against enemy attacks, but more importantly you are hidden from sight. Since there are many outlets and unprotected blind spots in a "Modern Warfare 2" map, it is nearly impossible to guard all areas where an enemy may attack. By staying close to the walls, you eliminate the blind spot directly behind you where your opponent may sneak up. This can help reduce your death count and helps you obtain a positive KD ratio.
Glance at your mini-map often, located in the top left corner of the screen. The green arrows represent your teammates, while the red dots represent your opponents. If you or your teammate has a spy plane deployed, you will be able to see your opponent before they see you. Although the spy plane does not detect the direction of movement, it does reveal the location, which refreshes every second. If an enemy approaches, crouch down and be ready to shoot. You can also throw a grenade or flash-bang to anticipate where your opponent will be.