There is no steadfast way to learn English, just as there is no singular way to learn any language. Different approaches will be needed. Obviously, paying attention to studies o instruction on the language in school, if you have it, will help. This will give you the theoretical background to assist you.
However, there are some things you can do to get a better feel for the language. The first would be to watch English television . Watching shows that speak English or news programs that speak in English will help you gain a grasp of how the language sounds and what the words mean. If you have a "closed captioning" feature on your television set, this will also help because it will allow you to read the words that are being spoken. I think that reading English publications or newspapers written in English will also help you recognize how the language is written and communicated. In the end, the best way to learn the language, like any language, is to speak it. There is often a fear in speaking another language because others might make fun of you or you might think yourself sounding "weird." Yet, you gain nothing by being silent. I am struggling to learn Tamil and I have so many people laugh at me when I speak it. Yet, when I speak it, I get it and understand it better. It is not about them. It's about you and gaining the comfort in the language. Find opportunities to speak it, make your mistakes, and I promise you that you will progress farther in learning the language than others who might not want to speak it because of how they might appear to others. (By the way, posting questions on sites like this one and reading the answers generated in English will also help you.)