I need some help..

.. I used to get 2.5 KDR with the Steyr Aug (like 1/2 years ago rofl) and now I want to buy it again to reach Staff Sergeant but I am really rusty with it (tried it in Alaska) so if anybody could give me some directions/help/help guide/ or give me link through to a help guide about how to use the Aug up the maximum also I am NOT going to try get the Aug Camo simply because I bought 150 crates and got no Aug Camo .. infact I bought like 800 GP crates in total and got nothing so yeah for me crates Fail and I am never going to buy them again

PS. Yeah I know alot has changed now like SCAR-L everywhere and stuff thats why I need the help even more