Just practice punching straight and short for now, also work on short punch counters to head and body. Later on you can work on angles, diagonal stepping, and shifts (e.g. rear-shifts, drop-ships) that will set up different angles. Also make sure you practice short punches when ever you can, shadowboxing, and bagwork, which will get you ready to practice it while you are sparring.

For elusiveness and versatility you should also begin to work on using your shoulder for defense. A trained shoulder can block and parry/deflect punches (works great against a right hand. If you are going to use your shoulder in your tactics make sure you keep your chin tucked and your right hand at your ready so you can either stay on guard and counter. Make sure you don't stick you head out when you roll your shoulder or you're going to get rocked.