The amount of available room you have for your dog is a key consideration for which one you choose to invite home. If you live in a small, one-bedroom apartment, go with a breed that weighs less than 50 pounds. Dogs that have an overabundance of energy are also not suited for small spaces.
If you live in an apartment or condominium, you also have your neighbors to consider, so avoid dogs that bark a lot if you can. Citronella spray anti-bark collars are available to curb this behavior in a safe way.
If you have a single-family home then, ideally, you have a fenced-in yard for the dog to exercise and do his business. If your yard isn't fenced, think about getting it done for your own convenience. Being able to let your dog out for a bathroom visit instead of having to take a walk can be a real advantage.