2. Writing regularly(fiction or nonfiction). I think it's one of the most awesome skills you can develop, and the younger you are when you start practicing - the easier it will be. Just create a blog, and try to regularly post something valuable there. It's truly awesome, in so many ways, and the longer you keep doing it - the more awesome it gets.
3. Reading and information diet. Trying to minimize inane internet browsing, news, social media, and maximize the healthy information that I consume. Audiobooks are the best thing ever. Enjoyable and satisfying to listen to, and incredibly valuable. Just get in a habit of reading/listening, and you will soon learn a massive amount of great information.