Packaging idea: Use your washi tape to make a pattern. Mix up the colors and make stripes across your package. Weave the tape or even make a diagonal crosshatch. If you accidentally mess up, just peel up the washi and reposition it.
Washi tape comes in all kinds of colors and patterns, so you are sure to find a few styles that fit into your brand's aesthetic. Washi can be functional as a replacement for plain tape, or it can be an embellishment.