Basically, for the backside ollie 180, all you do is turn the other way. But, there is one little difference that will help you out -
Back Foot Placement! For the frontside ollie 180, I had you put the ball of your foot a little to the heel edge of the skateboard. For the backside 180, slide that foot a little more towards the toe edge. You're doing this for the exact same reason - to help you spin the board with your feet easier. This way, on the pop you should get a little bit of spin, which should help you on your way!
But otherwise, you just want to spin your board and yourself in the opposite direction.
As with any trick, just keep practicing and you should have it down in not too long. Relax, and enjoy! If you have any questions, you can stop by the Skateboard Forum, or you can e-mail me!
