Contrary to what you might expect, merely doing a job every day does not necessarilly qualify as real practice. Improved skills come from focused practice and continually tackling challenges that lie just beyond one's competence. If work overload prevents this during the work day, make sure to set aside time in your week to avoid skill stagnation.
In this article Jeff Atwood likens the pursuit of programming skills to learning the martial arts, termed "code kata."
"I may drive to work every day, but I'm far from a professional driver. Similarly, programming every day may not be enough to make you a professional programmer. So what can turn someone into a professional driver or programmer? What do you do to practice?"