Begin. The rest is easy.

Oh man. Delay, procrastination. It's such a demon.

Lose this day loitering, ’twill be the same story

To-morrow, and the next more dilatory;

True indecision brings its own delays,

And days are lost, lamenting over days.

Are you in earnest? Seize the very minute:

What you can do, or think you can, begin it;

Boldness has genius, power, and magic in it.

Only begin it, and the mind grows heated:

Begin it, and the work will be completed.

--attributed to John Anster, also found p. 476 of the 1908 edition of Notes and Queries