RECOMMENDED READING
Hub Spot and Wistia have created a very good quick guide to shooting with video, it can be found here
Click here to know how to set up the video equipment.
Settings on the Camera
NB: YouTube uses 16:9 aspect ratio players. If you are uploading a non-16:9 file, it will be processed and displayed correctly as well, with pillar boxes (black bars on the left and right) or letter boxes (black bars at the top and bottom) provided by the player.