I love the colors! If you wanna try coloring a simpler way to avoid the white spaces when you Select, use a Clipping Layer Mask instead. I use Photoshop too, and when you Create a Layer above your Base Layer > Right-click for options > Make a Clipping Mask, it's a breeze to shade and highlight. Especially using the few extra layers to adjust the shadows or highlights without changing messing up one or the other.