I started colouring up Astronawoot, an initially black and white game I released online in february. It's a comic-based choose your own adventure game, with the original still playable here.
The trickiest challenge in this was to find a style that would look pretty from further away (due to how the panels are built), as well as allow me to draw it really really quick, so I can cover all of the 56 pages by myself in less than a month (it's not as scary to do it than it is to say it).
With those in mind, I managed to find the best style quite accidentally, while painting a shape with a darker colour. Seeing the strands of colour next to each other, I knew I hit something precious. Also in order to make the effect applicable to any area, I paint with transparent black, this way not having to constantly pick a darker shade of the current colour. I started getting the hang of it, so I'll be back with more... :D