Most important post of all. (along with the rest of the cat ladys posts)
For example: I have seen way too many people get a Husky or Malamute and wonder why the dog ate the sofa, and tables, and the remote control. It's a sled dog bred for pulling sleds in winter, not sitting around the house and just get one walk a day. The dog must fit your lifestyle, or you the dog's lifestyle/purpouse.
And don't get a complicated breed for your first dogs, get a "beginners breed". They are all "complicated" in their own way, but some are way harder than other. A German Shepard is much much easier than an Ovtjarka or Akita for example, or Pit Bull for that matter.
Google around and read up on different breeds, what they are bred for and what they like to do, and how much (and what sort) physical and brain exercise they need.
And when you have gotten your dog, do the training classes, they are actually a lot of fun as well.