As the surface of an item curves away from the print head, you may start to see the sharpness of the imprint decline. One way to maximize your imprint area is to use images that are more rounded in shape, as opposed to rectangular or square imprints, which may have to be printed at a smaller size to avoid fuzziness around the edges.
For odd-shaped items, taking a quick photo of the item. Using that photo to trace an outline of the shape in your graphics software can help you to create artwork that fits within the space and is positioned correctly on the item.
-Rachel Tindal, LogoJET