[Callers] alternate formations

HI all - I'm a fairly new caller and so far have only called improper duple, beckett, and 4x4. Where does one learn to call these other options? I haven't even ventured into squares because I don't know how to call them and don't know where to learn. I bought Nils and Ralph's book, but just reading a book doesn't give me the confidence I need to venture into different formations. In fact, a local caller recently called two squares that were disasters and another beginning caller and myself looked at each other, laughed, and swore we would NEVER call a square!! JoLaine