I specialize mostly in small hinged boxes. I prefer to include either an engraving, inlay, laminate, or other textures in the design of the box. I have recently begun to investigate copper patinas and expect to integrate that as elements in the boxes.
On the inside of the boxes I have experimented with natural/no finish, flock, mirrors, suede inserts (like in a jewelry box), and more recenlty with a variety of fabrics that add an interesting surprise when the box is opened.