Kozmo,
they are good drawings, you are getting shading.
The pencil contrast should be higher in my opinion, so the white specular would appear more.

the feather is effortless, try to see the values of it before you put lines, you made the easy and wrong way, look at hair to draw then you will get it.

About the last drawing, practice materials like glass, metal, you made well, but I dont get what material it is.