I started to draw the frame first with pencil then draw the object with a darker lines. After that I fineline it with a 0.3 fineline pen, this step I also fineline the inner and middle lines. I then fineline the outline of the object with 0.8 fineline pen to make it more interesting and have more dimension. I used marker to render and make shadow to make the shape more interesting. Finally I use soft black pencil to add an extra layer of shadow on the shape