Fancy Skull 2 says close your eyes and listen to his secrets... His secrets include a 4%+ infill and maybe supports, and perhaps something more sinister... but that's between you and it.
HAPPY HALLOWEEN!
Infill:
10+
Notes:
I have two models - the first one will require supports, the second one may not if your printer has lots of fans, but both models will require some sort of infill to support the bottom of the eye sockets.