Kill Confirmed is one of the most fun playlists in Call of Duty: Black Ops II because it forces people to move around the map to collect tags. There are still people who camp and snipe, but generally those players do not find a lot of success because they never bother to confirm their kills. It is easy to dominate Kill Confirmed with the right mindset and correct loadout.
First of all, you need to be willing to die to collect tags. Collecting tags is the most important thing in this game, not your kill/death ratio. Tags are what help your team to win the match. If you snipe someone from across the map and then nobody confirms your kill, you might as well have not even done it.
When you look at the scoreboard at the end of the game, the number one indicator of how well you did in this playlist is score. Since confirming a kill gives you +100 score, grabbing tags is the best way top the leaderboards. If you get 20 kills and 20 deaths with 25 confirms and 8 denies, then you did better than someone with 20 kills and 2 deaths with 5 confirms and 2 denies. Your score would be 3,700 compared to just 1,550. See how important confirms are?
To do well in Kill Confirmed, you also need to move around a lot. You can't hide in a corner or watch a doorway and wait for people to come to you. Sure you can get some kills that way, but it won't be fast enough to actually help your team. You need to be willing to run around and seek out your kills.
Many players are probably used to playing "conservatively." When you aggressively run around, your loadout must be tailored to that frenetic style of play. Here is what I recommend and personally use myself when playing Kill Confirmed:
Primary Weapon - Since you will be moving around a lot, you need to be fast and agile. That means using a submachine gun because they are light and allow you to remain quick on your feet. Personally, I prefer the PDW-57 because it has a 50 round magazine. This will allow you to engage groups of targets at once without having to reload in the middle of a gunfight.
Attachments - The laser sight increases your accuracy when you fire from the hip and is a must when using any SMG. Submachine guns are pretty much useless at long range so don't even try it. Since they are inaccurate at long distances, you will rarely need to aim down your sights with an SMG. Shooting from the hip is already pretty effective at close range but adding the laser sight makes it even deadlier.
Secondary Weapon - None. If you are using the PDW-57, you don't really need a secondary weapon because the 50 round magazine cuts down on reloads. If you are using a different SMG other than the PDW-57 (such as the Skorpion), you might want to grab a secondary just in case. I would recommend the KAP-40.
Wildcards - Perk 1 Greed and Perk 3 Greed
Perk 1 Slot - Lightweight and Ghost. Since the object of the game is collect tags, you need to be able to move fast to get them before dying. This makes Lightweight a must-have when playing Kill Confirmed. Ghost is also a good perk for Kill Confirmed because it keeps you off enemy UAVs. You don't want to just run straight into the enemy. Try to run around them. Ghost will allow you to flank your opponents without being seen, shoot them in the back, and collect all the tags.
Perk 2 Slot - Toughness. Using this play style, you are going to get shot a lot. Toughness is a good perk to have because it will allow you to continue to return fire and gives you a better chance to out-gun your opponent.
Perk 3 Slot - Dexterity and Extreme Conditioning. Although you won't be aiming down your sights all that much with an SMG, Dexterity is still important because it allows you to climb faster. This is necessary for quickly jumping up into windows or over walls when flanking. Extreme Conditioning is just an obvious perk to have in this playlist because it lets you keep running and increases your chances of getting tags before getting gunned down.
Lethal - Bouncing Betty. If you are using the PDW-57 and don't need a secondary weapon, taking a Bouncing Betty can be very beneficial. Let me make this clear, once you throw it down, you keep moving. Don't just camp near it waiting for a kill. Even if you aren't around to confirm the kill, having a Bouncing Betty on the ground can "block off" a certain area for your teammates and also lets you know when enemies are in that vicinity if they destroy it or get killed by it.
Equipment - None.
Optional Second Attachment - If you don't want to use a Bouncing Betty then you could also throw a Suppressor on your primary weapon. Like using Ghost, it will help you to flank enemies by staying off the radar when you fire. Extended Clip is also useful on guns like the MSMC.
Scorestreaks - Scorestreaks are more about personal preference than anything but I think it is important to avoid streaks that you need to personally control because this takes you off the battlefield and prevents you from grabbing tags. So stay away from the Dragonfire, RC-XD, VTOL Warship, and Lodestar. If you are running and gunning, you probably won't get enough points for the last two anyway because runners and gunners die a lot.
The three scorestreaks that I use for Kill Confirmed are UAV, Hunter Killer, and War Machine.