Read.
Read blogs, white-papers (if thats your thing), books (read books by the truckloads), read anything and everything.
Write.
Write down your views and opinions on whatever you are reading about. Make your point of view clear. Blogs are really excellent for this purpose.
Code.
Write code every day. In your head, on paper, in a compiler. On a train in the rain on your way to Spain. Write code every day.
Talk.
Talk with other programmers about programming. You will be amazed how often you A) never saw something from a particular angle, B) were flat out wrong, C) didn't know enough.