Astrology is not an exact science, like mathematics, it's not magic either, it's more like a human science, like psychology. Astrology consists of studying the influence of the planets at a given moment: at the moment of birth but also at a given date, in the past or the future. It is therefore a question of painting a portrait on the basis of complete birth coordinates (date, time, place) but also of examining the planetary influences at a given moment, for the whole planet (the world of astrology) or for a particular person.
Most astrologers study books but it is equally important to choose from which authors and especially to vary their sources. This way over the course of study they can refine their own perceptions and develop their own methods.
The best way to start is with yourself and your loved ones, so you can compare the descriptions you study to the characters you know best. Thus, little by little, you will be able to cross-check and realize that often the same causes produce the same effects.
If you are a good writer, you can also offer your services to some publications, whether on the internet or in print media, specialized or not. In this case, you will usually specialize in horoscopes (global forecasts for a sign, possibly split into decans).
To become a good astrologer, some qualities are very valuable. Above all, it requires a great intellectual honesty, one must be able to systematically question what one learns and to submit to the filter of experience, astrology is a discipline that constantly needs checking and refining. You need to be able to empathize, in order to better understand the expectations of your customers and put yourself in their place, or even on their level, to answer them in the clearest possible way.
One must be a little bit of a psychologist and inspire confidence: the sense of contact and the quality of the exchanges are essential bases for the exercise of this profession. What is well conceived is clearly stated: do not play sorcerer's apprentices with a subject that you do not know well. False or incomplete forecasts can do a lot of damage and destabilize fragile people.
Whatever your choice, prepare yourself for important discoveries in yourself and around you: Astrology unveils a lot about a person and it is likely that you will not agree with certain interpretations, especially if they are negative ... It takes time, hindsight and a good deal of wisdom to admit some of our less glowing sides. Expect too many contradictions. Often, a natal chart seems to say everything and its opposite, it does not mean that the interpretations are false. It just tells us that we are all full of contradictions, this exercise will show you the various sides of your temperament and should greatly help you correct some flaws while developing what's best in you.