Each artist has their own little quirks for getting their muse to sing but it all comes back to focus whether it is shutting off all outside distractions or closing off with music.
Figuring out how you best focus is a matter of trial and error, for some focus comes at the witching hour (drawing late into the night to find your work coming out really well) while for others it is a matter of conditions being just right (where if even a little change can ruin your art mood).
For me focus comes and goes as I go along, progress sometimes spurring it on.