This is what you need. Pencils, odorless turpentine, paper stumps, a nail file and of course a digi. Mostly I use 2 or 3 shades of color for 1 thing. Depending on the size I want to color. I do that to get more shadow then with just 1 color.
I start by coloring the flower. I use 3 colors and they are C130, C150 and C160.
Now it should look like this. You see you get more shadow then with just 1 color.
Now you first clean your paper stump with your nail file the get the color of.
First color the edges with C400 and blend.
Then use C410 and color the parts where you want the shadow. And blend.