Keep on playing the game and practice on singleplayer until you are a pro. I DO NOT suggest getting any mods or hacking. Play games like CS or something to improve your skills. Hope this helped.
I meant classes and perks and how to rank up and get squad points quickly
There's no such way to 'quickly' rank up. However, if you play all day then you may become a pro and start ranking up. Playing the game will only make you rank up and achieve perks. Look at the requirements you need to achieve a certain perk and aim to complete it, and you will get the perk. Hope this helped