This illustration enters the series of sketch exercises. Here are the steps for creating this sketch from a painting :
The first step lays the big bases of the sketch.

Digital Painting Croquis Pandore étape 01 Lady Melusine
The second step specifies the features and elements of the illustration.

Digital Painting Croquis Pandore étape 02 Lady Melusine
The third step is the longest, the realization of all the little details.

Digital Painting Croquis Pandore étape 03 Lady Melusine
After the sketch stage comes the laying of values (shades of gray), this is a first step towards future exercises.