If you want to learn how to hit a golf ball straight, you must first learn how to shape any golf shot. If you learn how to hit a draw, and then you learn how to hit a fade, you now have two very different FEELINGS. You can use these feelings as a kind of framework to work within to feel how to hit the golf ball straight.
Shot shaping is not something you should wait to achieve until you get to a certain standard.
If you can't shape the ball both ways, it's almost impossible to feel how to hit driver straight or take control of your irons. You will also see how by improving your FEEL, you will naturally strike your irons pure. It simply comes from a greater sense of what the clubhead is doing.