Although now days there is a lot of technology that makes fashion designing a lot easier and less time consuming. To be  a successful apparel and fashion designer one needs to be able to express ideas by hand drawing.

There is no computer o design tool that has the feel and expression of the human hand.
A competent fashion designer needs to practice a lot using pencils with their different grades(hardness).

Pencils used for fashion design
Each one form 9H to 9B allows to create different shadows, traces and scales of black and gray.