I studied the "hyper-illustration" style of Japanese photo-realist master Hajime Sorayama.
His process for photo-realism involves many unconventional techniques.
Think of the entire process in the same manner you'd build up a canvas if you are painting.
You add layer upon layer - using different densities of graphite as you go.
And between each new layer you blend, erase, blend, and erase again.
I've taken to using chamois and microfiber cloth to blend as much as I use actual cones.
I have fine-tip erasers that can be sharpened like a pencil.
Mechanical erasers (powered by a motor) like engineering/architecture draftsmen use.
And the most important thing is choosing a really dense, thick, surface to work on. Vellum card-stock or bristol board is perfect. Smooth and tight but not coated with anything that would make getting the graphite to sick difficult. Yet the fibers are tight enough that you're not tearing them if you erase a lot.
Lastly, in some of these I use white graphite to add highlights back in. This can give just the right amount of pop to eye light or skin reflection if applied lightly and blended.