Parallel Turns
A very simple technique: scissor your skates with your lead skate closest to the direction of your turn (i.e. for turning right your right foot should be forward). By tilting your body you should start skating on the outside edges of your leading skate and the inside of the trailing one. You should now be turning in the direction you wish to travel.

A much better turning method is the crossover. To obtain a much tighter turning circle and a lot more power this is the method you should use the most. It involves crossing the left skate over the right for turning right (and vice versa) and pushing with the right skate before picking it up again and bringing it back together with the left.