George Gershwin on inspiration
Out of my entire annual output of songs, perhaps two—or at the most, three—come as a result of inspiration. We can never rely on inspiration. When we most want it, it does not come. Therefore the composer does not sit around and wait for inspiration to walk up and introduce itself. What he substitutes for it is nothing more than talent plus his knowledge. If his endowment is great enough, the song is made to sound as if it were truly inspired.
Making music is actually little else than a matter of invention aided and abetted by emotion.