Personally, I've always developed multiple skills. From 10, I've played piano and been into science and computers. The key, in my opinion, is to practice daily, maybe 20-30 minutes of good focused striving.
For new skills, it's very hard and requires dedication, for instance I tried to pick up the violin. It's very hard initially due to the challenge of bowing properly and the second challenge of locating fingers properly to create the right notes. Yet, progress is steady even after 20 minutes a day, my playing quickly became much more bearable over the weeks.
