Writing for the sake of writing is all well and good. Writing because you have stories to tell or purely for the sake of the craft is fine but if you want to pursue writing as a career, you must write with purpose and that purpose is to get paid.
With that in mind, writing, like all businesses must be carefully thought out. Professional writers have a business plan. They think about marketing, production and efficiency.
I’m not saying place business ahead of the craft, but take into consideration the business elements when thinking about the craft. Consider not just plot, character arc, and structure but also market, distribution and production. Who are you writing for if you want to get paid? Ultimately you are writing for readers but your first readers, unless you go straight to self publishing, are generally editors. What editors of magazines and journals and book publishing houses are looking for is a tricky proposition.
Start with the basic economic questions:
What are you producing?
This is the part where craft is king. What are your strengths as a writer? Think about length (short stories or novels) and genres. Most people write general fiction. General fiction or literary fiction is a crowded market, making it tough to break through and sell.
How are you producing?
How much time can you realistically spend writing. How productive do you think you will be in creating finished product to send out into the market?
For whom are you producing?
What is your market? Do you want an agent? Are you targeting a book deal or magazines? When you have fully explored the ‘what’ question, the ‘for whom’ question becomes more clear.
Write with purpose. Write to get paid.