What transmission range do you need? Remember to take obstructions and topography into account. Expect actual transmission range to be 20 percent or less of the advertised range -- sometimes it's much less. Rolling topography, tall buildings and dense foliage further reduce a two-way radio's viable operating range.
Do you need a license? If you want or need to transmit at more than half a watt -- or if you want to be heard more than half a mile away -- you'll probably need to use GMRS channels, in which case you need a license from the Federal Communications Commission (FCC). You can apply for a license online at the FCC website. Licenses cost $85 and are good for five years.
Will you be using the radios in wet conditions? If you suspect you'll be using the radio in situations where it's likely to get wet -- on a lake or in the rain, for example -- buying a waterproof radio (or at least a water-resistant one) is a good idea.
Will you be traveling in remote locations for long periods? If you will be using your two-way radio for extended periods, consider purchasing a model that accepts alkaline batteries as well as a rechargeable battery pack. Alkaline batteries typically provide more run time than rechargeable battery packs, and you can swap them out for spares if needed.
Will children be using this radio? Large, easy-to-press buttons are helpful for adults, but they're even more important for small children.