Attach luggage tags to the handle and zippers of your bag. This is a fairly common way to identify personal luggage, so be creative. Tags come in all shapes and sizes, so shop around to find something unusual. A sleek black luggage tag might be nice, but how easily will it be spotted among similar bags sporting similar tags? Try a large sparkly cupcake tag, or something with a unique saying on one side. Use multiple tags to further separate your bag from the pack.
Use tape to "decorate" your bag. Whether you put a large "X" across the front with duct tape or use a variety of colors to form your initials somewhere else on the bag, this approach can make your luggage stand out from the crowd. Tape is fairly durable, so it will withstand the handling by the airline and on its subsequent journeys with you. Once you've grown tired of the design, tape is easy to remove and shouldn't cause any damage to the bag.
Turn this into an art project for your kids and let them go wild, and you won't miss when your bag comes rolling around. Pom-poms are also available online as common luggage identifiers, in a variety of colors and sizes. If you aren't keen on spending money just so you'll recognize your bag, throw something together at home -- tie leftover fabric scraps, or even an old dish towel, tight around the handle, and you have an instant luggage identifier.
Luggage huggers are sold specifically for identifying luggage and come in a variety of wild designs that can't be missed. They're sold in different sizes according to your needs, and are light and stretchy enough you won't risk damaging the bag or its contents. If you're going the cheaper route, wrap a colored plastic bag around the middle section of your luggage and fasten it with durable tape. Alternatively, you can use a colorful garbage bag and throw your luggage inside.
Handle wraps are simple and small and an effective way to personalize luggage without making an enormous statement. If the other options are too gaudy, loud or quirky for your tastes, a simple handle wrap can accentuate your luggage just enough to identify it in a sea of bags. Wraps are sold in a variety of colors and designs; and aside from personalizing your bag, they also make it a bit easier to carry or pull.