I have learnt that the use of Personas (composite character profile), which is basically creating a fictional character as an estimated example of your target audience, has become useful for helping to identify your audience for your design.
For example, I created three characters of which I think would be affected by my Biodegradable snack packaging; A manager for a chocolate bar company, an environmentalist and a college student. Each character I pretty much estimated a “journey” for how they would be affected if they discovered and used my product, in order to learn how I could amend my design to fit the needs of the consumer, if needed.
Or some cases discover other uses for my design. With my college student character for example, he discovers that the non-toxic, eco-friendly material used for my sweet wrapper can also be used for his pet gerbil to chew and tear up to turn into straw. The affect this has for him is that he no longer throws away the wrapping whenever he buys a snack.