If I might recommend a couple of books to you:
I like this book quite a bit because it breaks down to the shape and forms of the dragon and keeps the information simple and straight forward.
Jack hamm is an illustrator I admire, his advice on creating animals forms is something I have seen other artists use and recommend themselves.
I hope those books are of help.
On that great road, always and forever journeying forward to that shining city on the hill.