I recently discovered the Virtual Art Academy site and have subscribed to Barry John Raybould's free newsletter.
I can't stress enough how important it is to keep learning and trying new things. Perhaps when we get stuck in a rut or have a block its because we're bored. I forget to try other things - new methods, new ways to start, other materials, etc. I tend to think that any and all my time at the easel must be focused on a gallery worthy painting. In essence, I forget to play and enjoy the process as much as the outcome.
Going "back to school" is excellent way to revive your creative spirit, to push yourself to grow and to try new things just for the sake of play and experimentation. Even if you don't have teachers locally, there is a world of quality mentoring and lessons online. Check out the list we've begun in the right column and treat yourself in the new year.