Now, I'm not here to give advice on how to be an author because I'm not one yet. Authors are published. But anyone can be a writer by following these four steps:*
Read books in your genera. Read books that people recommend to you. Read something you thought you'd never read. Read books on writing books. Read actively with a pen and highlighter. Note what works. Edit what doesn't.
Notice what's going on in the world. Experience the world though all your senses. How things look, feel, touch, taste, smell. Listen to how people talk. Observe how the passage of time feels when you're doing something you enjoy or when you are board. How does it feel to look down from a very tall building? What's it like trying to walk though your house in the dark to find the light switch? Weave these experiences into your characters and story to connect with the audience.
3. Meet other writers
Talk about the craft. Read and critique each other's works. I have notices a huge leap in my own writing ability after starting a writer's critique group last year. Listening to what others have to say about my work helps me improve and looking critically at other writers works also hones my writing ability.
I know it sounds simple, but this can be the hardest part. To be a writer, you must write. You don't have to be a good writer at first. Like everything in life, we get better with practice. Write when you feel inspired. Write when you don't feel like writing. Write when you are alone. Write in your head all day long. Just. Write.
*Actually, you only have to do step 4, but the first steps really help if you want to be a good writer.