The lights are on
Before I start off let me just say this, this is not an expert guide that will instantly turn you into a quick scoping maniac but rather tips to counter simple mistakes that will hurt your performance, so here goes.
1) Do not, do not, do not use scrambler. This perk will hurt you more then it helps you. Picture this: Someone is sniping up in a second story window. They start to see their radar going white and they know someone close is using scrambler. They switch to thier secondary and camp at the top of stairs and wait for the person using scrambler. Do not use this it gives away that there is someone around and even though it might seem to help you stay stealthy, it is more like a flashing light screaming at your opponent COME FIND ME I'M REALLY CLOSE.
2) Do not overuse your sprint function. I constantly see people sprinting while I am walking with my gun up and we both look each other right in the eye and 99% percent of time the person who has their gun up will kill the person who is sprinting towards them. So yes sprinting is useful but dont overuse it especially in enemy territory or you will be seeing the respawn timer a lot more.
3) Move along walls in stead of running in the open. Very simple instead of running right out in the middle of a walkway move along the side of it to lessen the chance of people seeing you and give you more cover on the side where the wall is.
4) When you have a care package that is ammo or even UAV or counter UAV do not take it. By doing this you have two possibilities. One, your teammate grabs the ammo/UAV. You gain experience for sharing your care package.Who cares if if your teammate gets ammo? Ive never really needed it. If its a UAV your teammate is still going to activate for everyone and you get experience. The second option is that an enemy sees your care package marker. Dont forget though they cannot see what the item is only that there is a care package. Chances are one of those greedy enemies is going to try and run over and steal your care package where you should waiting for them ready to shoot them right as they try and capture it.
5) While using a riot shield the best way to get kills in my opinion is using stun grenades w/ throwing knife. Protect yourself with your shield until you have an opening like your enemy reloading and throw a stun. Be careful though if you try to stun while the enemy is shooting your shield you will go down fast. Then quickly circle around to his side or behind him and quickly dispatch him with your throwing knife while he is stunned. Then use scavenger to get your knife and grenades back.
6) I know you might have heard this one before but just in case you have not the easiest way to obtain a high level kill streak like a chopper gunner or ac130 is the killstreak combo of predator missile, harrier/attack heli, then chopper gunner/ac130.Get five kills then use the predator to hopefully get a double kill, call in the harrier, wait for it to get some kills and then hopefully get a chopper gunner. Alternatively, if you get an EMP, wait until you see one of these combos by the enemy and then call in your EMP instead of activating as soon as you get it. You will get more points based on how many killstreaks you destroy.
7) This one is kind of common sense but I hate it when people do this to me. Do not call in your harrier when your team already has one airborne. This forces your harriers to compete for kills earning less for both of you. Just wait until the other one goes away.
The last tip but probably the most important: Keep moving but always stay in control. Try not to get bogged down on one spot on the map because death will eventually come. Instead anticipate your enemies movements and flank instead of rushing the enemy head on. Always be one step ahead of the other team.
9) If you are ambitious and you have your setup to Harrier, pavelow, Choppergunner or something like that, and you are not getting at least 2 of the kill streaks 1 in 4 games. Lower your killstreaks to something simpler like a UAV Pred and Harrier.
10) a lot of people disagree but i say, never use long time remote control killstreaks like AC130 and Choppergunner, it leaves you too vulnerable. My friend has a KD of 4 something, and he uses a pred, Harrier, and Pavelow. Yes the remote control ones get you some decent kills, but it has a good chance of ruining your killstreak, because you cannot defend yourself
Any way I hope these tips help all those people who just got the game and are looking for some ratio boosters.