The most obvious -- and fastest -- way of creating privacy is to put up a fence.
Fences help keep your neighbors from seeing into your yard. They also provide a sense of enclosure and safety, making them a perfect option if you have children: Fences keep kids in and strangers -- or animals, such as dogs -- out.
Here's a hint: If you want to create a private space in your yard, look around before you build a fence. You might be able to use existing structures to create privacy. For example, tuck a small patio or deck next to your garage or home. Screening just one or two sides may be all you need.