Hi Sundarajan. Your question is very broad as there is not one protocol for immunohistochemical staining of tissues. A lot depends on the antibody, the antigen, the tissue itself (FFPE, OCT, etc) and other factors. I would suggest looking at the antibody manufacturer's suggestions and you can also find very useful information about IHC and many IHC protocols here: http://www.ihcworld.com/protocol_database.htm