Hiya! Loving your latest studies so far [: And the La madame corne branche piece is coming along nicely. If you want to experiment more with edge definition, I suggest you try to play around with the smudge & mixer brush tool in photoshop, they will give you really cool and unexpected results, especially the mixer brush tool.
Here are some tutorials to introduce the tools a bit:
Smudge tool tutorial:
Mixer brush tutorial:
This tutorial covers blending/painting in general, that might also be useful to you. Other tutorials by this artist, Ahmed Aldoori, are worth checking out btw.