Beginner POD designers usually assume the hard part is making the artwork. In reality, a lot of early failure comes from everything around the artwork: niche research, product selection, file setup, and listing presentation.
The most common mistakes
Poor niche targeting, low-resolution files, weak typography, generic mockups, inconsistent branding, and pricing without margin planning show up constantly. So does uploading too many average designs instead of improving a smaller number of strong ones.
How to avoid them
Research who you are designing for, build cleaner production habits, and review your work at product size instead of only on screen. Small operational improvements usually matter more than dramatic creative breakthroughs.
The good news is that these mistakes are fixable. Most of them disappear once you treat POD like a system instead of a lottery.