Is there a tattoo symbol for achievement?
I’ve been looking into symbols for my art coursework, and the closest thing to a symbol of achievement (bar somthing obvious like a trophy) that I’ve found so far is the Byzant Nonagram, a nine pointed star. http://www.byzant.com/Mystical/Symbols/Stars.aspx That might be a bit too obscure for what you’re looking for, but I hope it helps.