Step 1- Choose a printer that works with your camera.
You can choose a photo printer with a media slot for the same kind of memory card your camera uses, or a printer that connects directly, via proprietary cable, to your camera.

Step 2- What type of printer do you want?
The two main kinds of technology you'll see in photo printers are dye sublimation and inkjet.
Dye sublimation- (uses heat to reveal color on special paper) excels at continuous tone printing.
Inkjet- provides crisp colors, relatively inexpensive supplies, and print flexibility. Remember that a printer designed for photo printing will do a significantly better job at that than a general-use printer.

Step 3- Choose other features you need.
Portability- Some printers work with batteries.

PictBridge Direct Printing- A newer format, called PictBridge, enables you to print without a computer, as the camera directly connects to the printer.

Print sizes- Unless you're getting a printer for a very specific purpose, and are happy with limited print options, you shoud probably get a printer that can handle at least two different print sizes, such as wallet and 4"x6". Of course, with a printer capable of 8.5"x11" prints, you'll end up with a wide range of smaller prints to choose from as well.