I improve my typing speed with http://www.speedcoder.net/
Every time I hear a concept I don't know I make a flashcard and quiz myself daily. I also have a collection of problems to keep myself challenged, some are interview questions and others are common patterns.
Here are public decks for Python: • General Python - https://ankiweb.net/shared/info/1394656023 • Coding challenges - https://ankiweb.net/shared/info/223286091