You can't schedule creativity. At least, I can't. I can plan times when I want to put things together, make myself sit at the piano and figure out good chord progressions and melodies; I can stare at the page and try different phrases. Sometimes that works, and it is a good exercise in writing and composing. I find, though, that for me it often comes of its own volition and then not when I've expected it.
Last night after I dropped the kids off at choir and I was driving home, I got smacked with a new song idea. And I liked it. I kept repeating it, getting more excited about it as I came down the driveway. I muttered line possibilities to myself while I closed up the chickens for the night as they rolled their eyes and clucked "there she goes again...". This morning, I added a few more lines, changed some. I revisited the idea to make sure I still liked it, and I did.
And it's a secret. For now.