Start by putting your feet into ollie position. Bend your knees, and turn your shoulders opposite of the direction you want to go-sort of like winding up. As you straighten your legs and start your jump, swing your arms and your shoulders in the direction of your 180. Hit your tail on the ground just like an ollie, but when your drag your front foot up toward the nose, pull your front leg around in the direction of your 180. Then with your front foot, push out toward the nose, and lift your back leg up to level out at this point you should be 90 degrees-halfway around. To complete the 180, pull your front foot back, guiding the nose the rest of the way around, and push your back foot forward to help the tail around. Make sure you rotate a full 180 degrees, so you can roll away backwards when you land.