There are other great books out there such as Expert F#. The F# Dev center has links to many other "learn F#" articles. All of these are great.
But, something I found helpful is going "purely functional", and Haskell is the perfect vehicle. When you're forced to think only functional, and don't have the other "escapes" F# has, you bend your mind into understanding how you can accomplish things without using mutation or object-orientation.