I have the ability to drop outstanding games at times, sometimes even regularly throughout the day, but I'll often find myself making bad decisions, getting outgunned, and getting thoroughly scorestreaked by the enemy team without end, and it's not very uncommon.
I know I could have an above average or even pretty great overall record if I could pull the games I know I can every round, but it just doesn't work out that way.
IMO doing well is determined by about 60% awareness and 40% aim, which is why you find people camping in corners so often- they have terrible awareness. If you have good aim then you should probably try to focus on knowing maps/map flow, using the radar as well as using audio because it tells you A LOT that video doesn't, and having an rough idea of how spawns work- pretty much wherever your team isn't most of the time. If you're good at that then focus on aim which, if you have your ideal look sensitivity set and/or use stock or not, just comes with time.
EDIT: Also, I suggest using a sight, usually Red Dot, for improving aim. Even when it might seem like a wasted point if the gun has decent irons I still think it makes a big difference- also it allows you to shift to other weapons using Red Dot with a lot more ease.
Haha, it happens to everyone hun. I can go 35-0 in one game, replay the map, and go 24-12. It happens. But yes, having good knowledge of the map does help, knowing where the flow of the game is gowing so you won't have opponents spawning behind you. Generally, wherever part of the map your teammates are, you can pretty much consider safe, so focus on the areas that you don't control.
In dry streaks such as these, don't equipped higher end Scorestreaks (since you probably won't even obtain them), instead go for ones you know you can achieve at least a few times per game, increases your score per minute and helps maintain pressure on the opposing team.
Try equipping (if you don't already have) the Stock attachment for your weapon, and learn to strafe shoot, which is shooting whilequickly moving left and right, you'll be surprised by how many players will stay glued to their spot while shooting at you.
Surpressed weapons are a BIG help, even with the drop in power and range (unless you're using sniper rifles). Fact is, most players find other players simply from the red dot that appears on the mini-map when they fire their weapons. With you not showing up, they can only guess where your shooting from (hopefully it will be too late).
Lastly, keep an eye on the routes your team mates are taking, and where the primary action spot is. Than, try to find routes where you can flank the opposing team and shoot them all in the back (gained ALOT of triple's and quad's just from doing this). Especially deadly if 90% of the team is in one area (such as one of the buildings in Standoff).
If all else fails, than turn the game off and cool down. Play a few hours later. Would post more, but I'm half asleep as it is lol. Hope it helps!