For those curious, this is my process for making a final picture, from one of the most recent illustrations over at Drawn and Devoured.
1. The drawing. I usually don't go through too many roughs, especially for something easy to draw like a mermaid. You can tell I had some trouble with the bottle.
2. The transfer. I use a light grey carbon paper to transfer my drawing onto better, heavier paper. This way I don't ruin the good paper by drawing and erasing onto it, and the end result is much cleaner.
3. What the transfer looks like when it's done. It's super light, see!
4. I use India ink to draw the lines, and add shading. This is the most important phase for me, and requires a lot of thought, since I have to decide where I want highlights and lowlights, and ink both those areas. Also here I inked the scale texture separately, because I knew I wanted the tail to have both pattern and shading, but it would be hard to work with if I did it all on one layer.
5. I separate the inkwork from the white background in photoshop. I think the tutorial I got this trick from is probably one of the best things I ever learned (link). Locking the lineart layer, I colour and tint all the lines.
6. What the colour fill layer looks like without the lineart overtop.
7. It's all done! Some last colour tweaks may go into place.