A professional lawn is a sight to see; there is not a single blade of grass out of place and the trails and flowerbeds have crisp edges. Any home gardener can attain a professional lawn without the aid of a professional. All it takes is a little extra time and effort and a good pair of hand clippers.
Mow the lawn to is usual height, getting as close to the edges as possible.
Clip the edges where there is concrete or a structure with an electric edger, otherwise referred to as a weed whacker. Hold the electric edger at a 40 degree angle away from you and move it in a straight line against the lawn's edge. Begin slowly by looking back over the area you just covered so that you can verify whether or not the proper height is achieved.
Trim around trees and flower beds with hand clippers to avoid injury to the plants.