Definiteness of purpose is the starting point for all achievement. --W. Clement Stone
When you make a decision to start an endeavor, you have the energy and enthusiasm and motivation to get started. Over time this enthusiasm and motivation can diminish especially when the going gets tough. One of the keys to maintaining motivation is remembering the purpose of your endeavor.
Finding your why
I will use writing as an example.
Why do you want to write every day?
Because I want to become a better writer.
Why do you want to become a better writer?
So that my content is clear, engaging, and easily understood.
Why do you want this for your content?
I want people to think about these ideas and be inspired to take action to improve their lives.
How will it make you feel if people do this?
I will feel fulfilled knowing that my stories and honest struggles have allowed people to take action to improve themselves and achieve better experiences in life.
The purpose, the why is usually several layers deep. It is ultimately about how you will feel and what you want to experience when you achieve your goal.
When you are trying to achieve something great, dig deep to truly understand your purpose and why you are doing what you are doing. Never lose sight of this purpose, and use it as motivation to keep going.