Like most developers, you probably keep a running list of ideas for apps you might build. I do. They all seem promising and potentially useful. How do you prioritize what to build? One way I try to decide what to work on: I think of my comparative advantages.
Work where you have a comparative advantage. Consider the unique skills, insights, networks of people, networks of beta users, and marketing channels that are available to you as a result of your where you are today and what you’ve done in the past. What you choose to work on should take advantage of those things .
College students, like myself, will probably have greater insight into the social behavior of teenagers and twenty-somethings than other demographics . They have access to an extremely broad and dense group of fellow students, all close to their age. They have access to college-specific activities - dorm life, taking classes, parties, homework - and close access to a set of potential beta users in a narrow demographic, other students. A college student can access a huge variety of college-specific marketing channels - friends, clubs, campus billboards, club tabling, and classes. An experienced engineer will have a different set comparative advantages. An engineer might have insight into the problems companies face with software architecture, databases, servers, testing. An engineer will have access to a strong network of engineers, managers, and CTOs. An engineer might have better access to other marketing channels - meetups, invite-only networking events, and technology conferences.
Domain expertise is a subset of comparative advantage. A college student would be hard-pressed to build a better CRM that takes the market. They don’t have domain expertise. On the other hand, an operations leader with years of enterprise experience would be hard-pressed to build the next trendy social networking app. They don’t have any domain expertise. They don’t necessarily suffer from handicaps; they just don’t have any legs up on the competition - twenty-somethings with the same ideas. So they would be better off competing elsewhere and exploiting their own comparative advantages.
Take a moment to think: what are your comparative advantages? What networks do you have access to, both as a result of your location and your experience? What skills do you have? What kind of beta users can you test your projects with? What insights do you have as a result of your experience? What other distribution/marketing channels do you have?
I’m in college right now (after a hiatus). That’s why my latest side project is tackling the problem of buying and selling things locally - a quintessentially college student problem.
A cautionary note: This is only one way to think about choosing your work. Working where you have comparative advantages can sometimes conflict with other valuable goals. Examples include: trying becoming well-rounded, trying to change careers, and trying to learn about new technologies. In those cases you have to take other factors into account!
 I don’t use the term as precisely as it’s used in economics. Technically, comparative advantage is the idea that economies are better at producing different goods. Perhaps China produces cars more efficiently than software. Perhaps America produces software more efficiently than cars. Even if America is more efficient in absolute terms at mass-producing cars than China, the idea behind comparative advantage is that if America focuses on software, China focuses on cars, and both trade with each other, both will be richer than if they didn’t focus on their comparative advantages.
 I use the term “probably” very loosely, on the assumption that “you get the point.” None of these are absolutes. There are definitely college students who don’t know anything about their fellow students. There are definitely people 10 years out of school that have deep insight into teenage social behavior.