Here is a small section of an illustration I am working on for a client. Illustrating this particular book has been fun and challenging. I won't say too much about the project at this point because it has such a long way to go and some of the drawing elements I am still considering reworking.
My process is also slowing evolving but as of right now I start with a drawing on transparent parchment paper. This allows me to make changes by creating drawings on separate pieces of paper and then placing them under the original drawing to see if they work. It should also be noted that parchment paper is very conducive for erasing and reworking your drawing, though this characteristic does make it a little messy as well. Easy to smudge your drawing if you don't have something to keep your hand up off of the drawing.
After the drawing is finished I transfer it to a piece of watercolor paper and then start painting. If you draw this lightly in graphite there is no problem removing the drawing after the watercolor is finished. My watercolor technique is essentially drawing with watercolor. I imagine it is somewhat close to how you would use egg tempera. I have not been trained to use either, so I am pretty much making up my own technique (not an original John Kelley painting technique I'm sure. It's just what the medium allows).