Random tests have invalid punctuation. Spaces after the last sentence or two spaces in between words.

Just beginning learning Haskell and this is just marvelous. It's really like they say: Experienced Haskell programmers tend to write less code, not more.
How would I learn such things? Should I finally start to write a real application with a framework which forces me to learn stuff..? I'd really appreciate some recommendations, especially those with free resources, since I'm not in a position to spend a lot of money right now.