Understanding your camera - shutter speed. In many ways the shutter speed of a camera is the easiest to comprehend, press the shutter button, the shutter opens for usually a timed fraction of a second, letting light in onto the digital sensor (or film) to give the correct exposure, and that's it.
Well nearly, generally for handheld photography for the best sharpness keep the shutter speed above 1/60 sec to avoid a blurred image, and idealy keep the shutter speed higher than the focal length of the lens, so for example, with a 200mm lens on the camera keep the shutter speed above 1/200. Shutter speeds above 1/320 will generally tend to "freeze" any action, or movement in the subject.
Sometimes with action photography, a little blurring can impart a sense of movement, especially with a moving vehicle, keep the vehicle still, and sharp, but allow the shutter speed to fall off a little, perhaps to blur the background, or the wheels.
In the attached photo I kept the shutter open for 13 seconds, with the camera mounted on a tripod, in order to capture the light trails of the vehicles, as they passed through the junction.
Many sports / action photographers will tend to use their cameras in "Shutter Priority" mode, so that the shutter speed is directly controlled, with the lens aperture being set automatically by the camera.
Using your camera on a regular basis, and getting accustomed to the settings will yield the best results.