Move your body and lean forward for an endo, with a slight turn on the bars.
Give a twist from the waist to whip the frame in the opposite direction of the bar turn.
Stay tuned on the front until the rear wheel is above your target, then move back.
Once the rear wheel is nailed to the ground, move further back to lift the front wheel easily.
Give a twist in the bars in the direction you want to turn, as well as twisting the waist to the opposite side.
Stay tuned above the rear hub, for an easy spin on the rear until you reach the front wheel target.
You can nail the front wheel onto a precise spot by pushing on the bars while leaning forward. See this move in a video.
Learning your marks
To pivot on the front wheel, launch a small endo, without pushing it too far forward, and just before the rear wheel takes off, give it some rotation by turning the bars in the opposite direction of where you aim the rear wheel (if you want to whip the rear on your right, turn the bars on the left). Follow the move with your shoulders above the bars. The rear wheel will re-adjust right opposite the bars when you realign your whole body with your shoulders. Alternatively, just before the endo, give the bike a vertical inclination towards the side you want to send the rear wheel, and mechanically, as the rear wheel is lifted, the frame will turn around the headset tube on the same side. To turn on the rear wheel, push on the bars to eject yourself away from the front wheel while at the same time flicking the bars in the direction you wish to turn.
Follow some marks on the ground, and turn the bike around by lifting the front and rear wheels, one at a time. The body weight shifting is the most important parameter, because your mass is about 6 or 7 times the mass of the bike, and it will bring most of the inertia to any move you make with the bike. Practise some precision stops between pivots, by nailing the rear or front wheel to its final position. Start with less than 90° and build it up from there. If you are right-foot forward, it will be easier to turn on your left. To step sideways on precise steps, change the direction of rotation (say you move the front to the left and then the rear also to the left instead of to the right).
Mastering the move
Practice the move both clockwise and anti-clockwise, as in most trials zones, you won't have the luxury of choice. You can turn around endlessly by repeating these moves. By giving it more amplitude, you'll be able to turn over 180° on the front and over 360° on the rear wheel or bounce into a 360° backhop. That's just what you'll need for these classy 360° drop off. Though for turning 180° or more on the front, you must really focus on the bar spin while shifting your whole body weight above the front wheel. That is what will allow you to carry on turning smoothly, in balance right above the stem, without being dragged-off sideways.