Malcolm Gladwell popularised the idea that it takes 10,000 hours of dedicated practise to master any skill. Following this principle should allow you to eliminate activities that you are not willing to devote this much time to. Think you want to learn to play the banjo? Willing to practise for 10,000 hours before you’re any good? If not, drop it, and move on to your top priorities.
Source: learn.filtered.com