I just finished the SP so now I'll play the MP. But I'm quite far behind.

Post some good guides to the MP if you know of any.

I'll start this off with one:

http://denkirson.xanga.com/742784256/crysis-2/

Here is the best tip you will ever get:

Manually leave the server/lobby after each game or you will lose out on progress constantly.

Mk60 mod 0 with rapid fire shoots fast, use it, but dont move while usign it.