When I watched Rivers and Tides, the wonderful movie about Andy Goldsworthy, I noticed that he sometimes arrives in a new and foreign landscape and starts work on a piece that is very similar to a piece he has done before. For example he might draw a snake/river in the wet sand, or put leaves on a rock.
I realize that this is a very good way to get started, to get warmed up, to get the creativity flowing, to seduce the muses. It is far better than to sit there, waiting for inspiration to hit like a lightning bolt.
Better to repeat yourself, better just to get started with any melody than to sit there and watch the moment harden and disappear.