There are several techniques to achieve the backside 180 ollie - here are two of them.
The Scoop Method
1. Roll at a comfortable speed on flat ground.
2. Hit your tail as if you were going to do a regular ollie, but begin to turn your shoulders (so your back is forward) as you hit the tail.
3. Let your shoulders lead your body. Your hips will follow and will turn your feet, which will turn the board.
4. Keep your center of gravity over the middle of the board. With the scoop method, the tail of the board stays low to the ground, and you may land a little on your back wheels first.
5. Compress your legs when you have come around the full 180 degrees. This will absorb the shock and will let you be smoother as you roll away.
The Pop Method
1. Roll at a slightly faster speed than for the scoop - this will allow you more time in the air.
2. Pop your tail like you would for a normal ollie, but with more force than for the scoop.
3. Ollie almost straight up into the air, turning only slightly backside. When you reach the peak of your ollie, swivel your hips to direct the rest of the turn.
