I look to my daily life and those around me. I am fortunate enough to work in a co-working space (Affinity Lab in DC) that isn't only filled with technology companies. It's a diverse group of people covering all sorts of different fields from technology, to media, to accounting, marketing, pr, products, charities, etc. We talk, a lot. There are tons of problems everyone faces, some are common, some aren't. But you get inspiration. Maybe some are common among different areas, some might be common among the same niche. But having access to discuss your issues and other people's issues really helps me see the problems people encounter. Sometimes it's about sharing different solutions because they are solved (or there is an easier way, not perfect, but easier), sometimes you need to come up with something.<p>tl;dr: talk to people, it helps if you're part of a diverse community of people.