You are ready for the commitment of getting a puppy, raising it correctly, and giving that dog responsible ownership for their entire life. Now, what you need to do is research where you are going to get your dog from. There are 3 places to do this in no particular order. A Responsible Breeder, Animal Shelter (Humane Society, ASPCA) or a Rescue Organization. DO NOT Buy from a dog store/puppy store. Not only are you contributing to Puppy Mills, you chances of having a problematic dog is very high (whether it is aggression, potty training, health) because of the way they have spent their life up to that point.
Some important things to know when raising a puppy:

Human contact (interaction), with as many different people as possible, between the ages of 5 and 12 weeks is the most important stage for the dog to become comfortable with humans. When you bring your puppy home, he needs to get as much exposure to as many different things as possible, but you need to be careful as where to take him, as he will not be fully immunized until 15-16 weeks, and can get Parvo and other pathogens if exposed to it. Another important time in your dog's development is 6-11 months, so I highly recommend that their socialization and exposures to new and different thing continue through the first year of their life. With that being said, your dog's socialization should continue throughout it's whole life. This will help tremendously with your dog learning that meeting unfamiliar dogs and people is normal.

TRAINING TIPS
Teach your puppy to willingly give you food and toys when you ask for them.
Give them lots of positive experiences with people of all ages and gender. Keep interactions fun.
Once they have all their shots, take them to very public places. By putting a puppy in these situations, they will not be frightened by them later.
Socialize them with other dogs/animals often when they are young. But, make sure they are being supervised and being socialized with well-behaved, well-controlled dogs.
When a Pit Bull Puppy (small) shows aggression towards another animal or person: quickly snatch them off the ground, hold them face to face with you and give a firm 'NO'. Do not ever strike them, there is no reason for this, as your firm command will be enough to correct them.
Always monitor your puppy's behavior and correct it when necessary. The longer you let them get away with it, the harder it will be to correct them.
When your puppy does something right, always give them a 'good boy/girl'. Positive reinforcement will make them happy.
Crate Train. They will love it, and it becomes their own private house. Never use it as a punishment.
Teach them to walk without pulling. Only move forward when there is no pulling. This is a lot easier to teach when they are young.
Keep your puppy active and exercised. This will keep them from chewing and digging.
Take your puppy to puppy kindergarten classes. It helps and you two will have fun.
When it is apparent that the puppy understands a command, don't overdo it or they will become bored. Then they will stop paying attention and learning stops.
A puppy given the right exposure and reinforcement will be easier to handle as an adult.