Topic: I need help after years.

I've never really cared about this until now.

I've been playing the Call of Duty series for a total of 3 years now, starting at Black Ops then getting an older game then working my way up to here, where Advanced Warfare's release is near. My problem is that for 3 years I have been so frustratingly bad at every Call of Duty game. There was one game of BO2 that changed my mind, and that went on until my friend introduced me to HIS friends. They are insanely good, and all of them a higher level than me in every COD. The only friend who doesn't make a big deal out of this at least once in every session is the friend who brought me to this. And him I don't mind playing with, but I try to avoid playing with anyone else. In three years time, I've tried to improve my game, but to no avail. I figured that since I've been doing this for so long and it's stayed the same, I definitely need help.
Here are my K/D ratios for every COD I own for Xbox ( I need help on console, on PC I do fine )
Black Ops - 0.35 K/D
Modern Warfare 2 - 0.36
Modern Warfare 3 - 0.60
Black Ops 2 - 0.53

Practice.

Try to play differently. I usually try not to be overly aggresive and go play at a relaxed pace. I usually have a 2.0 K/D ratio on FPS.

You have to learn the maps inside and out, and know where players tend to hang out or respawn. This can be done by playing a lot and paying close attention, or by reading info/watching youtube videos. If you just camp in one spot you won't get many kills, and if you run around like a headless chicken you will get slaughtered.

Big, honest tip: ALWAYS move around the perimeters of the maps. If you ever find yourself darting directly through the middle of a map, you're doing it wrong. As others have said, camping doesn't work, either, and it'll make people hate you real quick. Find a weapon type that you really like, whether or not others consider it "overpowered." In other words, don't be ashamed to use a shotgun if people are hating on it lately if shotgun is YOUR best weapon. On the flip side, don't try to snipe if you're terrible at it and you're just trying to prove something to yourself. That means you're just digging yourself a hole at the beginning of every match.

Alright. Thanks, everyone. I'll try these next time I play. Should I play league or not on BO2? Sometimes people are being stupid and just want a good K/D on an objective gamemode, and they're dragging my Silver Division rank down. I'm now rank 88 and I should be at 55 or 60.

I've tried these, but they just aren't working for me. I went only around the perimeter of the map, not rushing through mid, using guns I like to use on Black Ops, and if I know every map on one Call of Duty game, it's Black Ops. I did this for a while and still went negative every time. In the beginning I did great, but that quickly went down. I even played Combat Training beforehand to warm up a bit. Should I just give up entirely on Call of Duty? It's been three years, and I still can't get it going...