Start with a sketch.
Carve your key block-- the one printed black with all the lines. It will be your reference for everything else.
Print as many prints as you will have other colour blocks. These do not have to be high quality prints. In the actual edition, the black will be printed last.
Using gum arabic or nori, stick the prints face down on other wood blocks. Mark which areas on each print will be carved. (In this case, I used orange highlighter)
Carve the other blocks, then wet them and gently remove the paper and gum arabic.
Print the blocks, starting with the lightest colour.
(Note the beautiful gradation that is a hallmark of the Japanese method.)
I'm printing another sixteen of the light grey tomorrow, on the "I don't know what I'm doing and am going to screw a lot of them up" principle.
And here's a closeup of the kitten: