Once you’re past setting up your initial schema and your sites gets users you’ll spend your time actively looking at your data, but also actively optimizing your database for performance. Understanding how to optimize Postgres is something any developer should be able to do as they understand the code and application best. The below documents provide a starting point for how to analyze your database’s performance and improve it. If you’re looking for further reading I’d highly recommend checking out the book PostgreSQL 9.0 High Performance. Greg Smith, the author, is a personal friend and knows Postgres Performance extremely well, there’s not a more definitive reference for postgres performance.