Never stop being a student. Don't ever let yourself think that you have learned all that there is, because a business owner with a mindset like that, is not going to be one for long. This hole is something it is even more important to avoid within tech-age firms, because it can be devastating to your mission as one.
If you "graduate" and stop learning, than you are stationary, when the world in which your firm operates is one that lives on the top of an always-moving wave. Just as I posted on the importance of maintaining a firm that is keeping up with the latest in technologies (see "Staying On Top of the Wave"), your staying on the crown of the wave is only possible if you yourself always remain open to a new lesson.
There are so many ways in which to maintain this learning environment; the most important of which is to subscribe to the literature in the field. Keep yourself connected with blogs (like this one!), and magazines that are designed to share the lessons that we are each learning separately.
So don't ever close yourself up and say that you are done learning. It's so easy for that wave to swallow up those firms who stop advancing, which has the danger of leaving your firm among those old-style ones we are beating.