I sketched in a procreate app.All of the shape start from a 2 point perspective block. I have used blue colour pencil for sketching and went over it with a fineline pen. I have uses a thicker line for the outside of the object or some where you cant see behind it.

I have added texturethat I like in every product. I have used the same technique as before to make the texture. I've darken the bit which I think would not catch light for example like a hole inside the object.

I have added the shadow and highlight as always. I have used dirty air brush for the shadow and clean air brush for the highlight. I have also added glow under the part which I think the light would shine.

I've added ground shadow to the shape to make the shape more stand out and look even more realistic. I analyse and consider where the shadow could cast if the light came from each direction.

Finally I have added the description of the material to make it more like a sketch.