Being successful in writing is much like success in life.
You need to set goals.
You need to define who you want to be/what kind of writer - what genre.
Attitude is important - complainers rarely win, and what agent or publisher would want to work with someone who complains about everything.
Skill is critical, but skill can be learned over time if you become a student of the craft, a student of others who have mastered writing, and if you keep learning and never give up.
And yes, success does require a bit of luck too, although I like to live by Thomas Jefferson's quote, "I'm a great believer in luck and I find the harder I work, the more I have of it."
I hear a lot of people complaining about the publishing industry. And I hear others that say - I wouldn't want to be so and so best seller because they have "sold-out" to the industry. But you know, if you're a writer and you believe in your book, then there are so many avenues available right now. If you truly want to be "successful", define what success in writing is for you and then make it happen. Not everyone will be accepted by the big publishing houses, but there have been many writers (through the span of time) who have found a way to be successful. Which reminds me about my post about rejection: All Writers Get Rejected. Even the most successful writers, have been turned down time and again. But they didn't give up. They stuck with it even if the doubts started to creep in. They stuck with it until it worked.
So don't give up. Define success for you. And write. Without writing, you are not a writer.