Efficiency is getting the most result for the amount of work you do. It can also mean accomplishing your work with the least amount of wasted energy. In terms of steering, efficiency refers to turning the wheel only as much as is necessary to make a smooth turn on the road.
When driving straight, the steering wheel will be centered on its axis. The farther you turn it to the right (on a right turn) the farther back you will have to return it to the left to regain a straight path in your lane. On right turns, you may have to turn your wheel 1 1/2 full turns to the right and turn it back as you straighten your car. Left turns should only require 1 full turn to the left.
If you turn the wheel more than is necessary, you will have to return to the straight position and then turn a little farther to get back in the center of the road, then continue with minor adjustments until a straight path is established in the center of the roadway. Learning to steer efficiently requires practice, but efficient steering will position your vehicle in the proper position the first time.