I'll start off by explaining the frontside 180 as I think these are by far the easiest of the two to learn first. Most people learn the frontside 180, usually just called a 180, as their next trick after an ollie. This type of 180 may also be known as a blind 180 as you are 180'ing behind you so you can see as easily. I think it is easier to first learn 180's with your front foot slightly further up the board than an ollie (Just behind the front truck bolts is best). Just before your about to pop the tail twist your waist slightly in the opposite direction your going to 180 and as you pop throw your shoulders and arms in the direction your 180-ing and this action should get you the full 180, if not then you can bring the board round the last few degrees with your back foot. THE B/S 180. The backside 180 proves to be a much more difficult to learn. It seems easier at first to spin your self in that direction but its harder to keep the board with you. The technique is similar to the frontside 180. Put your front foot just behind the front trucks bolts, turn your waist a little in the opposite direction than the one your going to 180 and when you pop your tail turn your shoulders quickly round to get the board to 180. You have to concentrate on controlling the board with your feet. If you dont get the board to do the full 180 it easy to skid your wheels the last few degrees. If you are finding that you cant do the full 180 and are landing on the board, slide your wheels round the rest of the 180 by dragging the board round with your back foot.