Determine your terrain. If you run mostly on paved sidewalks, trails or roads, you'll want to choose a road running shoe, the most common type. If you like to run on dirt paths or hiking trails, you'll want to choose a trail running shoes, which according to REI are "essentially beefed-up running shoes designed for off-road routes ... enhanced with aggressive outsoles for solid traction and fortified to offer stability, support and underfoot protection."

Find your shoe size. You probably already know your size for casual or dress shoes, but running shoes can be sized slightly differently. Some running shoes have particularly roomy toe boxes, sometimes with more room than necessary; you may need to go a size smaller. You also want to consider whether you have a very narrow or wide foot.

Determine your foot type. Feet come in three basic shapes: normal, flat and high-arched. A normal foot lands on the outside and rolls slightly inward to absorb shock. If you have normal feet, you do not require a shoe that offers motion control. A flat foot has minimal arch, and usually rolls -- or pronates -- excessively, which can lead to overuse injuries. Flat-footed runners need shoes with motion control. A high-arched foot is just as it sounds and requires more shock absorption and plenty of flexibility.

Visit your local running shoe store, a great place to go to either buy or browse for running shoes. Many of these stores staff knowledgeable sales people who are seasoned runners and know how to help you choose the right shoe. They will size your foot correctly and may have you run on a treadmill to analyze your foot shape and running style.