National Horticulture Mission has published an excellent guide on Organic Farming System. It includes almost all the operational details you will require - how to go about it, what is jeevamrutha and how to prepare it, what is Natueco farming, how to prepare land, enrich soil, how to intercrop and so on.
I am attaching the complete guide (PDF) with this message. I'm also including below the section on converting a farm from chemical farming to organic. Keep in mind though that the 26-page guide has a LOT more details.
Chandra, I think this thread can be pinned.
NHM_Organic_Management.pdf (237 KB)