In a previous article, I described why everything in life cannot be serialized and we have to keep juggling multiple balls all the time. Moreover, we can employ the concept of sequencing in an intelligent manner to spend a balanced life.
For me, one should start with his or her own inclinations, strengths and opportunities and list down a few big projects one wishes to accomplish during a lifetime. I have seen that life gives us multiple shots at great work for a period of time — 5 years for each project. So in total from 25-65, there are 8 shots to success and accomplishment available.
If you have multiple projects in front of you, I would suggest starting with the one you are most passionate about. Being passionate will force you to spend an insane number of hours on the project dramatically increasing its chance of success. The secret is to find something that consumes you. It should possess your mind. In the next 3 to 5 years, you can finish and move on to the next target.
And if your career is in a steady state mode, it is not a bad option to find a hobby you like and repeat the above process. Like planting a seed, you will see its fruits with time, the least of which is that your mind will become innovative and open to new ideas.