It works like this, cruise at a good speed, then do a normal Ollie, but try to land on the back wheel only. Pull up on the handlebars to keep the front in the air.
Tips
1) Set your feet so that you can balance without standing on the brake
2) Lean your body forward toward the handlebars
3) Keep the handlebars raise as high as you can off the ground to make this trick look good.
