I also had some issues with smooth pans. Best advice that my friend gave me was move from the hip or shift weight with legs. Moving the camera with your arms rarely results in a slow smooth pan. Also pan further than you need to and start BEFORE where you intend to start.
OR get a tripod with a pan head. and then practice the pan over and over. For the shoot I just did, it was 3 hours of shooting for 25 seconds of video that he chose to use. We practice each shot over and over and over.
Another option is to get a gimbal....then you don't have to worry about being overly smooth and can just let the electronics handle it.
Or a rail system.