Just some ideas:
1) Get an adult (puppies require frequent walks and, while adorable, are undoable unless you can return home every few hours) Adults can be anything from 6 months to 10 years old. You don't have to adopt an old dog, but remember that the younger the dog, the higher the energy level. Around 2 years, they calm down; ie, they don't run spastically through the house at warp speed.
2) Very small dogs, aka lap dogs (Yorkies, Chihuhuas, etc.) tend to be one-person dogs. If living alone with one person, they tend to be cranky with other people. If you don't want that, you'll need to put some effort into having people over to the apartment regularly, taking the dog to meet others, etc.
3) Very large dogs tend to dominate a small space. Many loyal and slightly blind fans of Great Danes, Rottweilers, Mastiffs, etc., claim that their breeds' quieter nature makes them excellent apartment pets - ie, the Danes are sleeping on the couch while the Fox Terrier is doing backflips off the ceiling. This is likely true; but the bigger the dog, the less space in an apartment, no matter how quiet that dog. And, to be indelicate, the larger the waste product you'll be picking up.
3) Some breeds make life as an apartment-dweller more difficult. Generally, it's harder to find an apartment if your dog is over 25lbs, and various breed restrictions can make it difficult to find a new home if your pet is a Rottweiler, a pit bull, etc.
4) Some breeds are harder to find than others; any shelter in America will have a purebred or mixed-breed Cocker Spaniel, Beagle, and 65 pit bulls and/or mixes. Fewer have Afghan Hounds or Harriers. But the sheer popularity of some breeds means that you have to scrutinize them closer - too many Cockers are snappish by nature, too many pit bulls are dog-aggressive.
5) Pet stores are the clean face of a nasty business; don't waste your money. Breeders, shelters and rescues are the way to go, but you should be cautious there too.
6) Don't get a dog with big exercise needs unless you can fulfill them onleash or have some secure place to run the dog. Offleash dogs in public places are a huge pain for everyone but the owner.