Look here for trends in advertising within these industry segments, as well as current trends in influencer marketing and the online marketplace.
U.S. business-to-consumer market research & psychographics
Statistics & studies gathered by market researchers, trade organizations, scientific publications, etc
National surveys like the U.S. Census can reliably answer "big picture" questions like, which ZIP codes in Texas or the U.S. have a certain percentage of young people? which ZIP codes are higher than average income?
Look here for insights around hair color, DIY vs. salon color, hair care, beauty products, self care in general, etc.
In particular, notice the vocabulary choices used in these sorts of articles, and see if those are useful search terms elsewhere.
