The Surface 90 is generally one of the first tricks to learn in kneeboarding.
Start out by getting directly behind the boat. A longer line will give you more area to spin on. Use a palms down grip. Quickly pull the handle to your hip. Rotate 90 degrees while keeping the handle as close to your waist as possible. Lean back slightly to prevent from catching the front edge. Now, spin back to the front. That's it!
Some things to remember:
Always look at the horizon. In other words, don’t look down; keep your head up. Looking down will throw off your balance and may cause the board to bounce out of control.
Keep the handle close to your waist at all times.
The next step:
Perform a Surface 180.