Admiring the wonderful nature, reading a book or watching a movie can be good inspiration, too. And friends.

Personally though, I'd say my inspiration comes from various sources (although it's mainly music and feelings). I never know where I'll get inspiration from.. I just get it when I get it. When I need inspiration to do something that I don't feel like doing but it has a deadline, I try to think about the theme of what I should draw a lot, and eventually I get the 'feel' for it.  Music helps as well (and it's the thing I usually use for inspiration), and so does walking my dogs (mind you, I live in a village, and a lot of my walks are in the forest or the fields. There's always something new to see - if not anything else, it's the smile-bringing excitement of the younger dog..) - if the theme I'm supposed to be working on is about nature.