Write a lot. Listen to advice when it is given, especially if you don't like the advice. Don't assume you are an undiscovered genius. At the other extreme, don't assume you are rubbish. Writing is a craft, like carpentry, and it has to be learned. It takes a long time to become a writer for all but the luckiest few. Only a proportion of those who are published will make any money from it. It is lonely, hard work, and often demoralising. If you can cope with that, get typing.