How to earn prestige points in MW3

In a breif awnser

New single player missions carrying on where we ended MW2

Two new online game modes

Kill confirmed - Pick up dog tags of killed enemies to be credited with the kill or freindlys to deny the kill

Team Defender - First person who dies drops a flag the team who holds it longest wins

Kill streaks redesigned and a new form added where every 2 kills you get a new perk and at 8 you get all perks unlocked (Hardline does affect this meaning 7 kills for all)

New Spec ops missions ( Can be done on and offline)

And survival mode ( Can be done on and offline) - players fighting endless waves of enemies with each wave getting more difficult

Along with this weapons now have a thing called Proficiency where you have to level your gun up by using it to unlock things such as reduced kick and impact

Essentially you lose everything. It's like starting over again from level 1.

This time around you can pay Prestige Tokens to get early unlocks, (ie, the AK-47 or Steady Aim at level 1) but the weapon/perk/gear's status is reset and you will have to level it as you normally would on each Prestige. For instance, if you had gold camo on a gun and all the attachments, even if you use a prestige token to "Unlock Gear," you'll lose the attachments/camo and you'll have to level the weapon again.

The only thing that is saved from one prestige to the next is any Titles and Emblems you've received from doing challenges. The challenges themselves reset, however. If you're really close to the end of a challenge that unlocks a title or emblem, it might make sense to finish it before using your Prestige.

You also get to keep the quantity of custom classes, although your custom classes reset to the defaults when you Prestige. You'll also not have access to custom classes until you reach the level where they unlock on the first pass.