You said you needed a tutorial with how to pillow-shade sprites, but it's really quite easy.
Recolor everything inside the outlines to white, and recolor all the outline to black. You use the darkest shade and go along the outline (sometimes second darkest so that it doesn't turn out too dark), and once you've finished going around the outline (one pixel, by the way), you start the next color with the same process. Continue until you run out of colors/space.
Hope this makes sense, haha. If it doesn't, message me or Server_Crash, please.