Name the style before the subject. “Tattoo design” alone gives you a generic drawing; “American traditional tattoo flash, bold black outlines, limited palette of red, gold and sage” gives you something a shop would recognise. The structure that works: “[style] tattoo flash design of [one subject with one or two details], [linework description], [color rule], centered on plain white paper”. The linework line is the important one — “single-needle fine line”, “heavy solid black fill”, “stippled dotwork shading” and “bold 3mm outlines” are what separate the styles from each other far more than the subject does.
Ask for flash-sheet framing — a single design centered on plain white — rather than a scene or a photo. That is the format artists read, it prints as a reference sheet, and it converts to a stencil far more easily than a rendered illustration with a background. Every design below is the unedited first output of its prompt on BananaBanana. Explore concepts on Lite at $0.03 apiece, then re-run the direction you like on Nano Banana 2 or Pro when you want the linework crisp enough to hand to an artist.