A. Subspecies: Some species have sub-species. Sub-species are basically Breeds. Example: Dogs are a canine species each breed of dog is a sub-species of the canine species.
A. Height/Length: This is basic. How tall and or long do you want your creature to be? Length or height is really your choice since it can be applied to any creature and both can be applied to a creature if applicable (My Fell Drake is described with both length and height)
1. Dimorphism? Is there a difference in size between males and females? Usually the females are larger with some species (some birds of prey for example) while sometimes the male