Set your feet up like you would for an ollie.
Place the ball of your front foot toward the middle of the board and slightly below the front bolts.
Hit your tail as you would for an ollie, but instead of dragging your front foot up the board, drag it toward the side of the board with a flicking motion. The faster the flick, the faster the flip. It's all in the ankle.
Stay over the board as you are jumping and the board is flipping (it's important not to push down on the board once you're up so that it can continue to rise).
Let the board hit your back foot once it has flipped completely. This is called catching the flip. Your front foot should not be far behind in getting back on the board, but the back foot usually catches it first. This allows you to control the trick on the way down.
Land with your feet as close to the bolts as possible.
Do another one.