This young illustrator does beautiful loose pen & ink sketches and then pains in loose, vibrant layers of watercolor and gouache (I think). As one who can't get enough of bright colors, I am absolutely in love with it. I can learn something from the looseness in her drawings; it's something I struggle with as a naturally meticulous person.
Also check out her blog - not in English, but lots of great sketchbook stuff that does not need translation.
via Design Work Life