If you want to be good on this game, you anyways need to use Aimbot, Wallhack or use cash.
Because on this game, there is like 90% of cashers who is buying SMG's and spraying like hell and doing most of the time Headshots or simply using hacks, some is using both of them, so all of what i can tell you is try to found another game than this shitty stuff by SGi one