You need to examine your lifestyle first: how much time will you have to spend with a dog; how much exercise time (walking, playing outdoors, etc.) and how much space; do you have a fenced yard, what kind of family situation do you have (small children, elderly family members, etc.). Ask yourself how much time you want to spend on grooming a dog, what your budget can handle as far as food and care, what kind of dogs appeal to you, and what kind of personality you really like (playful, serious, clown, dignified, intense . . .). Do you like large, medium or small dogs?
That will give us something to start on.