I wish every prospective dog owner could read this thread! But, if they can't do that, here's my second choice:
Every propective dog owner should understand that dogs think differently from humans, and be willing to learn about it, preferably from an experienced, reputable trainer. If you can't do that, at least read some books on the subject. ("Culture Clash" by Jean Donaldson is one great one, also "The Other End Of The Leash" by Patricia McConnell). If you don't have time to do that - well, you probably shouldn't get a dog, but if you do anyway, know this, at least:
Dogs do what works, meaning that they get something that is a reward TO THEM for doing it. Dogs stop doing what doesn't work, meaning they don't get things that are rewards TO THEM when they do them.
So, to me, the three bare-bones "rules" of dog training are:
1. Reward behavior you want.
2. Don't reward behavior you don't want.
3. The DOG decides what a "reward" is.
(I.E., you may think yelling at them or pushing them away is a negative thing, the dog may think it's a great game! You may think a vigorous rub of the ears is a great reward, the dog may hate that. Take the time to learn what YOUR dog thinks is a reward.)
But really, they should just read this thread.