To begin, make sure you know how to hula hoop. Stand straight, with your knees slightly bent and your feet planted firmly apart. Start by holding the hoop around your waist, so most of it is in front and it is touching your back. Then, give it a twirl in a counter-clockwise motion, and simultaneously begin moving your body in a circular motion, going back and forth to ensure that the hoop keeps spinning around your waist. Get into a gentle rocking motion, alternating your weight from one foot to the next, to keep your balance and maintain the motion. Practice until you get the basics perfect, and only then will you be ready to progress t0 newer moves.
Once you are an expert at basic hula hooping, try doing the Ringer as a starting trick. Hold the hula hoop around your neck with both hands, and bring it forward, so the back of the hoop touches the back of your neck. Now, give it a gentle spin to start it off, and start moving your body in a fluid circular counter-clockwise motion, so the hoop starts spinning around your neck. Keep your body moving in the same circular rhythm, to keep the hoop spinning.
Another simple hula hoop trick to try is the Knee Knocker. To perform this, hold the hula hoop around your knees, and give it a start by spinning it in a counter-clockwise direction. At the same time, begin moving your knees in a steady circle, maintaining a constant speed and holding your arms out straight at your sides, to keep your balance. As long as you maintain the circular motion, the hula hoop will keep spinning around your knees.