Making good work is half the job. Getting someone to actually buy it is the other half. A few basics that make the difference:
Price with context
Buyers don't know what art should cost. Give them something to compare against, size, medium, edition number, past sales. Context builds trust.
Photograph it properly
Even the best piece looks cheap in bad light with a phone camera. Even, natural light and a clean background do more for sales than any caption.
Tell the story, briefly
A line or two about why the piece exists gives buyers a reason to want it beyond how it looks. People buy meaning as much as image.
Make checkout easy
Clear shipping timelines, real return policy, no friction. Confused buyers don't buy, they close the tab.
None of this is complicated. It's just consistency, applied over time. If you're starting from zero, go back to the field guide and build from there.