There is no rule of thumb when it comes to package design in terms of, “do this and your package design will be effective”. This is because just like advertising, marketing, and brand identity, it will always be different for every business. Every business has a different product, personality, target market, marketing objectives, etc.
As I showed you in a previous post, the package design should be inspired by the brand’s personality. A great way to give your package design a unique style is to also be inspired by the product itself. It could be the product’s color, size, shape or materials from which you pull your inspiration. This not only makes it more interesting but also keeps it more consistent with the product inside the packaging.
My favorite example of this is in the Doritos concept box design below. Since the Doritos chips are distinctive triangles unlike all other chips, the designer has decided to repeat this design throughout the package design.