There are a lot of different camos to unlock in Call of Duty: Black Ops 2.
All of the camos in the game are unlocked for individual weapons, so you have to complete challenges for each individual weapon in order to unlock camos for it. The camos are all kept when you Prestige though, which is nice.
When you’re in Create a Class, click on a class to edit it and highlight a weapon. Press Y on the Xbox 360, or Triangle on the PS3 and you’ll be presented with the camo selection screen. You’ll be able to set any camo you currently have unlocked for the weapon, and you’ll be able to see your progress toward the next unlockable camo as well.
The challenges to unlock camos have to be done in order. You’ll start with headshots, and you’ll unlock several camos up until you get 100 headshots with the weapon. Once you complete all of the headshot challenges, it will change to Longshots, and so on.
Here are all of the challenges you have to complete to unlock all camos for an individual weapon, with the exception of Diamond Camo, which requires you to finish all challenges for all weapons in a weapon group.
If you want something even more extravagant, check out my other article to unlock Diamond Camo for your weapons in Black Ops 2.