Before you can learn how to use a lawn edger, you need to choose one. This is one situation where landscape-savvy neighbors and the salesperson at your local home improvement store can come in very handy.
You can use an edger or a string trimmer. Edgers come in wheeled and stick (or pole) varieties. You can also choose between gasoline and electric, or get a manual hand edger that you power yourself. (Keep in mind, however, that this can be time-consuming if you've got a large expanse of lawn.) Gas tends to be heavier and noisier than electric, but it's better for cutting through heavy tangles of weeds and brush. Prices can range from about $20 to $200 or more, depending on the number of bells and whistles you choose. You don't need an expensive edger unless you're a pro or you need to do some heavy-duty trimming.
Before you power up your edger, make sure you're being safe. Wear long pants and glasses or goggles to protect yourself from injury, and earplugs or other protection to cover your ears. Some edgers can produce 85 decibels of sound -- loud enough to damage your hearing [source: Consumer Reports].
When you edge, point the blade between the edge of your sidewalk or driveway and the grass. Watch out for trees, mailboxes, flowerbed edging and other obstacles. Not only can you damage these objects if you hit them, but the contact can also wear down your edger blade. Dig a slight trench as you go, to give your lawn a nice sharp edge. Discard the grass and weeds you've removed in a garbage can or lawn bag.