Here's the process for my last pic. ^^
First I bust out my lineart! Original lineart size was 1777 x 2055 px, but I generally do my linearts when one of the dimensions are at least 3000 px.
Since I wasn't working too well with colors that week, I decided to paint in grayscale for the time being.
Then I work out how I want the background to look~
On a new layer under the lineart, I fill both Mukuro and his owl with a solid gray, lock transparency, and start painting the general feel.
Whenever I want to make adjustments, I make a new layer above the solid gray one, create a clipping mask for it, and start painting over it. If I like how it looks, I merge down and start again on another new layer above it. I do this until everything is nice and clean. :D
(Poor Muku needed some eyelashes. xB )
TIME FOR THE FUN PART. Since colors weren't working so well with me, I decided to cheat and work in grayscale first. Well, it's time to "color" it! Create a new layer ABOVE the lineart, and change its blending mode to "color" (lol xD). In this mode, you can pick any color you want, and the grayscale colors will adapt to that color without that dull feel than if it was done in multiply mode. You can also blend the colors quite smoothly without switching to normal mode, so that's a definite plus too. (:
Here, I thought his coat was a little too bright, so I made an adjustment layer and lowered its brightness and contrast.
Final part~ I forgot that the inside of his coat was red until the last moment, lol. OTL I made another color layer, filled it with red, and made it so that it only fills the inner coat parts. Afterwards, I made another layer for the lighting, filled it with light pink, and set it to linear light at 60%. Finally, I add a watermark if I'm satisfied with out it turned out, and post it online... XD (watermark's not shown here though)
Aaaaaand there you have it! Hope you guys liked it~ (: