Scott Hanselman in his 72nd podcast  tell about the ways to become a better programmer in six months. He mentions few things:

  1. Read books.
  2. Read good code.  There is a question: "which code is actually good"? Any code that is used by programmers. So any popular open-source projects, like RSS Bandit, datBlog or Subtext. Also, the code that is actually used by a programmers, e.g. Castle Project.
  3. Talk with the people outside your comfort zone. Don't sit in the office. Go for a lunch, talk with someone from different company about their development cycle or tools used.
  4. Find an intern. Interns bring fresh minds into the team. They have different wider view on the projects you work on.

And finally, the most important point: if you have a goal, write it down.