Ethnography: it's way, WAY more than just following someone around while they shop. Learn what it is, what to consider when performing an ethnography, and how to be sure your ethnography is inclusive!
References mentioned:
Paco Underhill, Why We Buy: https://www.amazon.com/dp/B001QA4SY2/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1
Trendwatching: https://trendwatching.com/
