When you start looking for a puppy you want to know what kind you need. You want to research how well they'll fit in to your life and how you'll fit into their's. Some breeds need more excersize, food, and atttention then other breeds so it's important to look at how much effort you're willing to put in and choose a puppy from there.
You need to puppy-proof your house just like you would for a toddler. You need to remove your elctrical cords, dangerous chemicals, and anything valuable from where they can reach. You can instal baby/pet gates to keep them out of certain rooms and put valuables in higher shelves. Just remember that they can climb, jump, chew, and scratch.
Before you get your puppy you need to make sure that they will have everything that they will need. They will need a cloar with identification, a bed, a kennel, bowls for food and water, a leash, and chew toys. As your dog grows you may need to purchase bigger collars and raplace worn out toys. Beds and kennels can be bought in a bigger size for the future.