I can't seem to find the link for adding sellers to my Favorite Sellers list. It used to be below the sellers user name.
Also, you used to be able to add a note about the Favorite Seller right when you added them to your list, but a while ago this option disappeared. This was very helpful as when you add a few sellers to your list it is hard to remember who was who when you have to go later to your Favorite Sellers to add your notes.