Hey, so I got a servo a while back for my arduino out of a kit and it has NEVER worked for me. I broke it down into the SIMPLEST of code to get it working but I have got nothing out of the servo except for a little bit of sputtering and gear clicks until it dies. The servo is 100% accurately hooked up to the arduino.
My guess...rubbish power supply, probably a little PP3 style 9V battery.
Either that or "100% accurately hooked up" is not correct. You're probably committing all sorts of terrible sins like connecting the servo to the Arduino 5V pin and maybe even through a breadboard.
Of course as it has "NEVER worked" it could always be a bad servo. They do exist.