Spend some time in production

If you can, spend some time working in the production system. I recognize that this isn't possible for everyone, but if it is, don't pass on that fantastic opportunity. It's probably not something you have to do every day, but if you can work with your software in it's production envrionment (perhaps even side-by-side with a production user) you can learn a lot about how it works, it's issues, and some of the challenges the software faces.