Woody Allen says “If you work only three to five hours a day you become very productive. It’s the steadiness of it that counts. Getting to the typewriter every day is what makes productivity.”
There is enormous power in routine, and doing the work each day, even if for a short period.
Do the work each day, find ways to move forward each day.
The most productive thing to do is to wake up early if you can – get the work in before the day interferes and people call you, your email starts.
I can't do that, I am not a morning person, for me, it is night that I am most productive, when it is quiet, and the day is done and I can focus. I call it going internal.
Always do something every day, even if it is for a few minutes, because it builds every day you do it.
You need to do something constructive each day because it builds your future.