This is a great question and I'm looking forward to answers from those who are better at this photography than I am.

Here is a first-timer's guide to photo shows, published here on Blab -

scroll down for newbie guides
http://www.modelhorseblab.com/blabpi...-contests.html


And here's one that is a bit more comprehensive, needs a little updating ...
http://www.modelhorseblab.com/blabsh...ower_Guide.pdf