Well guns like Enfield, MPL, 74u, FAMAS, AUG, FAL, Galil, Commando, AK47 have good sights so I would use Dual Mags as an attachment. Also pick up guns as secondary backup. I usually shoot from behind cover, rush the outskirts of enemy spawns, rush for a few kills, then back up. I pay attention to my HUD, NOT JUST CHASE RED DOTS ON SPY PLANE. For instance if I see the skull symbol or a Blue or Green Arrow disappears, I know the enemy is near so I try to listen for footstepts and kill them.
Killstreaks I run when I'm in a party are Blackbird/Rolling Thunder, Chopper, Dogs or Gunship(when it worked)
Killstreaks I run when solo or on a scrub team are Counter Spy Plane or Napalm, Blackbird, Chopper Gunner.
You'll have a better chance at big killstreaks if the enemy is full of splitscreen noobs. I usually play in a party, because the less splitscreen guys you have on your team, the better chance you have...Also don't camp in one spot or camp where your teammates are. I dont suggest camping unless enemy has Chopper or Gunship in the sky....I can't tell you how stupid people are to keep running out when they KNOW a chopper is in the air, ESPECIALLY if they arent using Ghost Pro. It's not worth dying 3-4 times just to try and shoot down a Chopper Gunner. You're especially stupid if you get spawned INSIDE a building but keep running out.
But I have three main types of classes.
I'm in a party, or solo with a decent team class
AK47 or MPL with Dual Mags with Law Secondary to take out Spy/Counter Spy Planes
Hardline Pro
Sleight of Hand Pro
Marathon Pro
Flash, Frag, Claymore
I'm playing solo with a TERRIBLE team class
Commando Silenced &

ual Mags or Stoner unsilenced. Pyton Secondary
Ghost Pro
Warlord Pro/Sleight of Hand Pro.
Marathon Pro
Concussion, Semtex, Claymore
I'm playing on a big map class
G11 or M16
Hardline Pro or Ghost but I only use Ghost if my team sucks and give up air support, Spy Planes all game.
Steady Aim.
Marathon Pro.
I also have an emergency class. I play Ground War mostly so if in Dom we are struggling for flags class
Galil or MPL with Dual Mags...
Flak Jacket Pro
Sleight of Hand Pro
Tactical Mask Pro.