“I want to sell custom products” is too broad to guide a catalog. A customer moment is more useful: decorating a first apartment, finding a personal holiday gift, launching team merchandise, or building a coordinated nursery.

Choose products your audience already knows how to evaluate. Apparel buyers think about fit and wearability. Wall-art buyers think about room, dimensions, and visual scale. Gift buyers think about meaning and presentation.

Work backward from a retail range the audience can understand. Subtract production, shipping, marketplace fees, returns, advertising, and a contribution target. Then launch with a question you can actually evaluate.