Our arms can move in many directions. But in boxing, we label the ways in which the arm travels to deliver a punch. A straight punch from the lead hand will always be a jab, a punch from the rear hand that travels horizontally across the body will always be a cross, etc. etc.. The fighter whose blows are quick, straight, and thrown with proper body mechanics, is going to possess the more effective punch.
The forward, back, and side step is so simple. Yet, I see many boxers crossing their legs, taking long steps, so on and so on. These are bad habits to get into because they cause you to get off balanced. It wouldn't take much to get knocked down. A weak punch will send you down if you're off balanced. You may not be hurt, but it counts as a knock down!
Here's the truth about boxing; YOU ARE GOING TO GET HIT. You can decrease your chances of getting hit by learning some defensive maneuvers. Parries, shielding, shoulder-rolls, slipping, and weaving. These techniques need to be implemented into your fighting style if you expect to have any success as a fighter. Let's start with the most basic defensive move; the shield.
Being able to do something is easy, but to do it well, whenever it is called upon, consistently and effectively requires drill work. Drilling a technique is the only way it's ever to become an effective technique. If someone says, "I learned how to punch and I'm ready to get in the ring," they're lying. You have to use drills while working the pads, hitting the bag, or with another person. Only then will you have a chance of executing the technique in the ring.