Instructions
Increase your controller sensitivity by going to the "Controller Options" menu from the "Modern Warfare 2" main menu. This will allow you to track targets easily, and will increase your turn speed greatly. A higher controller sensitivity can take some time getting used to, but can also make up for slower reflexes as it only takes a small flick of the finger to get the drop on an enemy.
Stay close to your teammates when you are playing the "Team Deathmatch" or "Domination" game modes. Your teammates will be able to provide cover fire for you and guard your back. You may also be able to steal a few kills from them, as many opponents will be injured but not killed by your teammates. Use these opportunities to score a few easy kills with little risk.
Learn each map by playing them several times. Run through each area of the map, stopping to look for any vantage points each may have. Notice where each objective is, and where the enemy is spawning. Spawn points change frequently in "Modern Warfare 2" and you can capitalize on this by learning each point. Players who spawn are often not prepared to fight for several seconds, and they can be easy targets.
Check your radar often for signs of enemy movement. Enemies that run, fire or kill your teammates are marked on your radar screen with small red dots. Keeping track of your radar can allow you to prepare for enemies approaching your position. It is important to know where enemies are in "Modern Warfare 2," as it only takes a few seconds to kill or be killed.
Use appropriate weapons for the map you are playing. Use the Spas-12 shotgun for urban maps, such as "Skidrow" or "Favela." The Spas-12 is a very powerful shotgun with a large spread and range, perfect for killing enemies quickly in confined spaces. Use assault rifles or LMGs for bigger maps such as "Afghan" or "Rundown." These guns will allow you to take advantage of a good vantage point, and are highly accurate as well. One of the biggest keys to a higher k/d ratio is bringing the correct gear for the situation.