I've been a professional coder for a several years. The comments about my code have generally been the same: writes great code, well-tested, but could be faster.
So how do I become a faster coder, without sacrificing quality? For the sake of this question, I'm going to limit the scope to C#, since that's primarily what I code (for fun) -- or Java, which is similar enough in many ways that matter.
Things that I'm already doing:
Write the minimal solution that will get the job done
Write a slew of automated tests (prevents regressions)
Write (and use) reusable libraries for all kinds of things
Use well-known technologies where they work well (eg. Hibernate)
Use design patterns where they fit into place (eg. Singleton)
These are all great, but I don't feel like my speed is increasing over time. I do care, because if I can do something to increase my productivity (even by 10%), that's 10% faster than my competitors. (Not that I have any.)
Besides which, I've consistently gotten this feeback from my managers -- whether it was small-scale Flash development or enterprise Java/C++ development.
Edit: There seem to be a lot of questions about what I mean by fast, and how I know I'm slow. Let me clarify with some more details.
I worked in small and medium-sized teams (5-50 people) in various companies over various projects and various technologies (Flash, ASP.NET, Java, C++). The observation of my managers (which they told me directly) is that I'm "slow."
Part of this is because a significant number of my peers sacrificed quality for speed; they wrote code that was buggy, hard to read, hard to maintain, and difficult to write automated tests for. My code generally is well-documented, readable, and testable.
At Oracle, I would consistently solve bugs slower than other team-members. I know this, because I would get comments to that effect; this means that other (yes, more senior and experienced) developers could do my work in less time than it took me, at nearly the same quality (readability, maintainability, and testability).
Why? What am I missing? How can I get better at this?
My end goal is simple: if I can make product X in 40 hours today, and I can improve myself somehow so that I can create the same product at 20, 30, or even 38 hours tomorrow, that's what I want to know -- how do I get there? What process can I use to continually improve? I had thought it was about reusing code, but that's not enough, it seems.