Sample search terms to try:
millennials or gen Y and marketing
generation x or gen xers and trends
boomers or baby boomers and attitudes
college students or undergraduate(s) and lifestyle
Databases to try:
Related Journals and Trade Magazines
Find these in JournalFinder, and then use the "search within publication" option from within the online databases!
Journals and trade journals to consider:
European Journal of Marketing
Journal of Consumer Behaviour
Journal of Marketing Theory and Practice
and many others ...
Other sources to consider:
Society for Marketing Advances Proceedings