One of the most trusted approaches is to use the Pareto Principle, which is more commonly known as the 80/20 Rule.

The 80/20 Rule states that, in any particular domain, a small number of things account for the majority of the results.

The 80/20 Rule is like a form of judo for life and work. By finding precisely the right area to apply pressure, you can get more results with less effort. 

A new path will never look like the most effective option in the beginning.

• The 80/20 Rule will help you find the useful things in your past and get more of them in the future. But if you don’t want your future to be more of your past, then you need a different approach.
• The downside of being effective is that you often optimize for your past rather than for your future.

• Given enough practice and enough time, the thing that previously seemed ineffective can become very effective. You get good at what you practice.
• The process of learning a new skill or starting a new company or taking on a new adventure of any sort will often appear to be an ineffective use of time at first.
• Compared to the other things you already know how to do, the new thing will seem like a waste of time. It will never win the 80/20 analysis.
  

But that doesn't mean it's the wrong decision.