Motion Preview

Motion preview
1. A longer (slower) shutter speed captures more movement.
2. Securing your camera and adjusting to shutter priority mode.
3. Because even small changes will make a big impact upon the shot so its better to shoot in a mode that gives you full control over the shutter speed.
4. Small apertures, decreasing the ISO, having a neutral density filter and panning.

Using Slow Shutter for Action Panning
5. set a shutter speed between 1/60 sec and 1/15 sec in Shutter Priority mode or Manual mode.
6. its important because the center will be focused and the background will be blurred. Thats how it should be in order to capture your main point clearly.
7. While continuously shooting the main subject will always remain on focus.

One Shot versus AI Servo Auto Focus Modes
8.  AI-Servo tracks focus on moving subjects so as your subject moves closer or moves further away your camera constantly updates focus to keep the subject as sharp as possible.
9. It can be used as both focus tracking and One-Shot.

What is Back Button Focus?
10. You don't have to worry about refocusing while shooting multiple times. 
11. if you have a still subject and hold down the AF-ON button in Servo mode, the camera will keep trying to work to find focus. So the subject will start going slightly in and out of focus because the camera thinks it should be looking for a moving subject. Basically its only better to use for fast/motion photography, not still life photography.