Beginning skiers tend to dig their edges into the snow for control, but this often results in catching an edge, making turning difficult.
Side-slipping is an easy drill you can do on snow to learn how to control your edges. Think about spreading peanut butter on bread. If the knife is held at a low angle, it's easier to spread. Pretend your skis are knives, and visualize spreading peanut butter on the snow. A flatter ski slides smoothly, whereas a high-angle ski cuts into the snow. To learn how to turn your skis more easily, practice this exercise until you can release your edges and sideslip in control down the entire run.
-Linda Symms, Bogus Basin, Idaho