The ancient Greek "oral poets" all had this anxiety about the deficiencies of their memories and always began poems by praying to the muse to help them remember. The invocation of the muses may have been a purely formal element by the time we encounter it, but it very likely reflected a real sense of the anxiety that the memory of forgetting could induce in a sensitive artist of an "oral society."
To feed your Muse, then, you should always have been hungry about life since you were a child. If not, it is a little late to start.
When inspiration does not come, I go for a walk, go to the movie, talk to a friend, let go... The muse is bound to return again, especially if I turn my back!
Inspiration is the windfall from hard work and focus. Muses are too unreliable to keep on the payroll.
There is no place for grief in a house which serves the Muse.
O! for a muse of fire, that would ascend And monarchs to behold the swelling scene!
Who knows where inspiration comes from. Perhaps it arises from desperation. Perhaps it comes from the flukes of the universe, the kindness of the muses.
I have always believed that opera is a planet where the muses work together, join hands and celebrate all the arts.