wow nice work on the texture for the raptor. it looks very good.
I do have a critique but you’ve already done so well i dont know if i should say anything XD
ok ok, you might have noticed this yourself, maybe not, but your dragon has no spine. If you look at any dragon pictures, or dinosaur pictures, they usually have some sort of spinal column, bumps or grooves. your dragons back is smooth like a snake. Even so, it looks very believable.
as to the question about the wings on the dragon. Take a high res photo of a patch of skin, face, whatever (i mean HIGH res). Bring it into photoshop, desaturate (CTRL-Shift + U) and adjust the levels so that its just white with black lines (you may have to play around with things, brightness/contrast, saturation, levels). once you have the wrinkles ready cut out a 256/512/etc size chunk that you like and save it, open Zbrush and select it as your alpha. paint away. I think Zbrush has a couple brushes like this in the default alpha library, take a look, they might have what you need already. if not, make a handful of these wrinkle patches and alternate them in your sculpting to get realistic creases, wrinkles, veins, etc.