Prov. Beginning a project well makes it easier to do the rest.; Once you have begun a project well, you do not need to put in much more effort to finish it.

Who said once begun is half done?

“Well begun is half done.” - Aristotle.

Where there's a will there's a way meaning?

Definition of where there's a will, there's a way

—used to say that if someone has the desire and determination to do something, he or she can find a method for accomplishing it.