After a normal drive around town for example, put your hand near the wheel/disc. If you feel quite abit of heat coming off, chances are its a siezed caliper. Compare the temperature with the other wheels to get an idea of how warm they should be. You could also jack the car up and try spinning the wheels by hand. They should spin freely. Also listen for the discs catching in places. and not to be offensive or anything but just remember the handbrake is on the rear wheels lol just some people i think forget that.