... in Illustrator.
First, place a high-contrasted image (high-key image, in this case my model Iva into Illustrator work area.
There is a bunch of tracing software and plug-ins out there, but for this example I decided to do tracing manually with pencil tool.
Use your imagination, draw something that you imagine, not just what you see.
In order to get a right side of the face copy+paste left half, mirror and join to get the full picture, and then draw an oval shape around.
Make some basic elements like simple flowers, leaves, circles and stains.
On the other hand, if you need this illustration for any purposes and don’t want to bother going through all this then get it here...