In relation to audience, a thought crossed my mind, to which some consideration may be given in this context. It is the question "How much knowledge can I expect my audience to have?"
This is an excellent question.
As a general rule, I would say it does depend on your target audience. Certainly I would expect an adult not to have to be told what a dragon was, for example, or anything else that might easily fall under the heading of common knowledge.
Anything more obscure, I tend to explain as I go. We all tend to develop areas of specialist knowledge, and it is very easy for us to assume that our readers know things we consider 'simple' - but it is certainly not always the case. I remember having to rewrite a scene or two myself in order to explain things properly when nearly every one of my readers asked me what the heck happened and why! This is not a mistake I care to repeat, I assure you <img src="/ubbthreads/images/graemlins/biggrin.gif" alt="" />
Most readers read a story to be entertained, and nothing more. If you delve deeply into realms of specialist knowledge with no attempt at explaining anything, you will lose a mainstream audience very quickly.
So my rule is always to explain anything that the reader must
understand if they are to follow the plot and enjoy the story. That way, they will understand what is going on, even if I have slipped up and given them insoluble riddles on the minor stuff <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Hope this helps <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />