I'm still working on Cofagrigus, but the process I'm using (due to a lack of skill with computer tools alone) takes a long time; it goes something like this:
1: Draw the card and scan it.
2: Make outlines using paintbrush tool.
3: Add proper color.
4: Add proper shading and minor details.
Repeat 2-4 for every part of the card (Cofagrigus, Yamask eyes, walls, floor, shadow background).
5: Resize it.
6: Make proper-sized suit.
Even though I reduced the size of the original drawing (which was much larger than the required size), it is still taking quite a while.