What do you mean by "a successful writer?" Do you mean one who is published by a publishing house and has hundreds of thousands of copies of their book bought? If you do, you'll need to be very, very exceptional in what you have to say in your book. And if it's fiction, chances are - if the old system of publication is the way you want to go - about 3 in a 1,000 of being accepted, let alone becoming successful.
Non-fictional stuff might be a little easier to have accepted, but still very difficult. So don't ever write with the sole goal that of being a successful and highly paid writer. Your chances will be slim indeed. However, if you write because you love it, feel compelled to write, then do it. If you enjoy it, do it. If not...well...forget about becoming a writer. After all, just about everyone in the world feels they can write a book. Most don't even attempt it.
However, don't let what I've written here put you off. You can self-publish. Or even simply write and get your stuff printed and placed into book form. And with these latter ways, you can be far more sure of your work appearing in print.