To become a reader, you must learn to switch your mindset from yourself and onto another person as the center point. Your focus is centered on the inner workings of that person as it relates to the world they live in. For this you need to go within to engage that part of yourself that communicates with the universal mind where all knowledge resides. The first requirement. Just like learning any other skill you need to practice.
Nothing comes to anyone without practice and reading another person is no different.
Remember, you already have the ability, you only need to tune it and refine it. Mind set is important. The more serious you are about it, the faster you will develop your ability to give readings. If you are dedicated to learn, you will. Just remember, Rome was not built in a day, so be patient.