In general you can charge more over time as your skills improve, but it also will depend on the client's needs, as some clients don't really care about the quality of writing and just want a quick article on the cheap, while others are willing to pay a premium for a well-written article.
As a writer myself I've catered to a wide range of needs over the past 20 years, from writing a simple PR all the way to a real estate listing for a $10,000,000 castle in Croatia and a massive job writing 130 wine summaries for an online store.
The main thing is to become good at your craft. Don't become a writer if you don't like writing, just because it's a thing you could do. Someone on a microjob site approached me recently with an offer to write, but their introduction was so full of mistakes it was painful for me to read, so I told them to maybe try doing graphic design instead. Not everyone is cut out to be a writer just because they can put words together in a sentence.