I don't know if anyone will listen to my advice, but in the last month I downgraded all my settings and went from being about .5 KDR to positive KDR with a sniper.
DEAD SILENCE, DEAD SILENCE, DEAD SILENCE! If I am playing like a 2v2 or something and my teammate doesn't have DS then I will refuse to play till they get it, because when you are near each other they fuck you by not having it. (I know it is rude, stubborn, inconsiderate, etc but it will save your life)
I think we all know to have good equipment (pc, headphones, etc) if you don't have good headphones find a room with good acoustics and crank some volume.
Equipment (Clays, c4, etc) Go with clays or bando, anything else is a waste, I usually pick bando, but all about the situation.
Don't be afraid to use the enemies weapon. It is weird, but on S1 I have run out of ammo and picked up an M4, AK, MP5, or something and done REALLY well with it.
Killstreaks: Don't go crazy calling in the killstreaks. Wait a second before calling in airstrike. I used to get an airstrike and call it in instantly, but I would get killed. Wait, if you want a successful airstrike don't get killed, fend off attackers and call it in. Worst thing that happens is you lose it and get a heli. WAIT ON THE HELI. Wait tell you die, then call in a heli. I know you want a 20 killstreak thanks to your heli, I don't care. Call in the heli when you die and It will rebuild your killstreak.
UAV Jammer: In 1v1 to even a 5v5 or so, this perk is priceless. Count less times I have been able to sneak up, or camp and surprise someone around the corner with this perk.
Other perks: Sleight of Hand is not necessary. UAV jammer, stopping power and Juggernaut are much better used perks.
Guns: Maybe the most important. All depends. I use an M4 with red dot and an M40a3. Be wise, if you can't fire fast don't you a semi auto. If you are shooting across the map, don't use SMG. Pistols, Deagle and Colt 1911 have too few bullets and M9 is too weak. Use USP, 12 shots, one hit kill, in hardcore.
Patience, you pop around a corner see someone, and walk back. Don't run around the wall all bullets flying, wait, and then when they come around kick ass.
Sorry for not summing it up. I will repost with it summed up.
I hope my time was well spent, a lot of you may not listen to me, but in 1v1 honestly I could beat a lot of you guys. My overall KDR is average, but I am beast in 1v1, and this is why.
PM me for more info, or more detailed.
---------- Post added at 05:07 PM ---------- Previous post was at 04:36 PM ----------
DEAD SILENCE!
Bandolier or Clays, anything else is worthless.
Don't be afraid to use the enemies weapon.
Wait tell you die to call in a helicopter, it will rebuild killstreak for you.
UAV Jammer, or else!
Pistols: USP 12 shots, 1 shot kill
Stun Grenades: It gives you a hit marker, very useful.
All summed up