Can you recommend procedures to increase volume of the hair or generate a hair growth from all the potential hair follicles?

There are many approaches to thinning hair. The simplest is to use a topical preparation such as Minoxidil or if you're looking for a drug free alternative, Revivv. Oral nutriceuticals are helpful such as Votesse, Nutrifol or Viviscal. For a more robust reaction, I can recommend PRP.
Working with a hair loss specialist is recommended.
Jeff Rapaport MD FAAD
Realself Hall of Fame

There are many treatments that you can follow before a hair transplant or in combination with it, remember that the hair transplant will fill the spaces of the hair that you already lost but the medical treatment will stop the progression of the hair thinning: you can try from finasteride 1 mg per day, oral minoxidil 2.5 mg or topical minoxidil 5%, twice a day, the most advance treatment are the stem cells from cord blood, this with just a couple of application plus medical treatment you will have a lot of regrowth.

Hi,
Medical and other ancillary treatments for hair loss really depend on what is causing your hair loss. Can you provide more detail and possibly photos?