How we make windmill to rotate in only one direction ?

Wind turbine blades are aerodynamically designed such that they can only rotate in one direction.  Like the wings of aircrafts, which are shaped to only give upward lift, similarly wind turbine blades rotate in the direction designed for.  The turbine yaw control system also ensures that the nacelle is always pointing into the predominant wind direction to maximise wind energy yield. This means that regardless of which direction strong winds come from, they will always rotate in the direction designed for.