First, you need animal facility (rabbit, mouse, rat,...)
Second you need patience, from preparation of your product to inject, passing by animal immunization with primary then boost injections, to blood collections and polyclonal antibody characterization against your product. Purification is optional as serum separation is sufficient.
For monoclonal antibody, you need to fuse B cells from immunized animal with cancer cells to obtain hybridomes, which you will have to screen against your products.
Third you need brainstorming (or maybe it is first), for the preparation of the product to inject; what to inject for success?
For example if you want to immunize against a peptide, you have to bind it C or N terminus to a carrier. So because you don't want binding with lateral groups, you have to protect these lateral groups for not reacting with the carrier, then bind to the carrier, then unprotect the lateral groups.
So you need: peptide synthesis (facility), chemistry, animal handling (facility), immuno-assays, cell culture...
I will add it exists companies that will do it for you.
But yes it is possible to do... I did it during my PhD (22 rabbits, 11 immunogens)... long time ago...
Hello! For all kinds of antibodies you need only one thing - enough patience. But to be serious: polyclonal ABs are relatively easy to produce, you don't need any serious equipment, while monoclonal ABs require a lot of procedures and process of their development is full of bottlenecks - clean isolation of B-cells, fusion (there are a lot of methods) and selection.