The pencils I use are Lyra ArtDesign if you’re interested. I found them the smoothest of the ones I tried.

The eraser pencil is from Faber-Castel but to be honest if other brands exist I’d try those instead. I find the Faber-Castel one a bit too harsh and yet not hard enough to really keep a sharp tip. It feels and looks similar to a pink school eraser. I’ve not had mine stain that I can remember but there have been reviews complaining about that.

The book I mentioned is called Course in Pencil Sketching by Ernest Watson. I’ve mentioned it briefly before here and here.