Well, do you currently hold a PF? If so then be smart about it.
Buy /ONLY/ one Pistol and Shotgun at a time (assuming you picked 1 handgun, 1 shotgun, 1 rifle) NEVER buy 2 Deagles/Shotguns/Rifles at the same time, EVER as it's the easiest way to get banned.
Also, do it at night, or generally...