What should I know before adopting a dog?

I want to adopt a dog after seeing a video of what happens to dogs who live in pounds. Our local pound is a kill shelter and I am going to look in a few days hopefully. What should I know before I adopt a dog? Also do they come with any supplies or a package of their current food? I've never adopted a dog before. My dad has always gotten purebred dogs out of good lines. I myself prefer mutts since my smartest pets were mutts. What questions should I ask? If you can help me please let me know soon. I want to go check out the dogs as soon as possible.