Do recall reading Your original posting ARNAUD.Arm, I see you have cut tree of these. Don't know were to start to give good advice.
There are so many treads here that you can learn from. Try to read everything about design, you will learn a lot from it if you are willing.
I made a quite similar mistake on a very small knife before starting "design for my pocket knife. It is also a Kershaw and I still use it every day.
Here is that link design for my pocket knife
arnaud
Friend aRM,
On this one.....first the good news.
Some of your elements have beautiful, flowing shape.
Now for the not-so-good news.
You have no proper point of origin for your center starting scroll.
Most of your shading is over done and to EVENLY dark.
It needs to have more taper to each line, starting lightly and with some space between.
Each line should evenly converge and get a little heavier as it flows towards the meeting point at the base of the leaf.
This creates a gradulation of gray shades, light to dark and gives the 3-D look that is normally imparted by the direction of the light.
Please see Chris M's classic recent shade post in answer to one of your past ones.
As it is much of your shading has the same constant degree of "blackness" as the textured negative background areas and imparts a blotchy look to the design.
With some fine tuning, you will get there. Your artistic ability is easy to see.
Best to you. Give this some thought