As someone who sees the value in all things, be it math, sports, reading, or anything obscure you can possibly think of, I often find myself struggling to stay on task with a specific goal.
While I was surfing the net, I came accross this post that highlighted one of my greatest fears - becoming involved in so much that I end up achieving nothing.
One thing that I've noticed that helps is having a top-down approach: Start by thinking about where you would like to end up once everything's been said and done. Once you know exactly what it is you want to do, then start thinking about the path that will take you there. As obvious as this may seem, most people tend to have no direction in life and simply accept what comes at them in life. Having a concrete goal with an envisioned route to get there is always advised yet rarely done.
As an example, I want to have a career in accounting or finance. Although I currently have two different endpoints in mind, the list of productive activities has been narrowed down significantly. Thus as much as I'd like to devote my time to learning Java or Python, these two activities will most likely not aid me in getting a job in either of my desired fields. Conversely, learning VBA programming provides me with an essential skill that I can then leverage to attain a great position within a company.