I just finished Anne McCaffrey's Dragonflight, the first of her Dragonriders of Pern series. I read it years ago as a teenager and thought I'd give it another shot as a grownup when I saw the audio-book version at my local library. I wondered if it would live up to my fond memories of it or end up like G.I. Joe or Voltron, making me wonder what I ever saw in those poorly scripted things.
It turns out that, although the prose waxed a little purple or melodramatic in some parts, and I found some of the characters inherently flatter and less likable than I remembered, one thing remained true: Anne McCaffrey wrote a terrific and rich setting filled with incredible detail. I'll go over some of those things she got right.
Physiology - One thing I didn't notice before but did this time around was how much the dragons slept. They typically fed on one or two herd-beasts a week. That doesn't seem like much for dragons that could fly with human riders on their backs but does when you consider how the dragons seemed to sleep as much as they did. They conserved energy when not necessary so that they had the energy to lift their massive forms in the air when they did need to be active.
Economy - A herd-beast a week doesn't sound like much until you multiply that by five hundred dragons multiplied by six weyrs (the homes of the dragons and their riders). Comes to a weekly demand on the world's economy of over three thousand head of cattle per week at the height of the Red Star's passing and daily thread attacks (space-borne spores that devour all organic life they encounter, what the dragons were bred to protect against). For an agrarian society with limited farm technology, that is a massive consumption of the world's resources.
Social Structure - To support such incredible demands that the dragons need to keep the world safe from the thread, the six (and later seven) weyrs are supported by a semi-fuedal system of holds (similar to kingdoms or city states) which pay tithes to the weyrs for their protection during the 50 years of threat every 200 years. Guild-like craft-halls support the education and skill sets required to run daily life among the holds and weyrs and pass on the knowledge to the next generation. Each is its own entity with its own desires and motives, and sometimes infighting among factions of the same group.
Many fantasy or science fiction worlds gloss over these details of the setting but the good ones don't. No nation in the middle ages could possibly support an army with five thousand knights. As amazing as that is to imagine, the economic cost of armoring, arming, and mounting that many highly trained men on well trained horses would be staggering. A society with mages that could easily teleport people and goods all over the world would not hide in remote towers but would become the local parcel and mail delievery service. When writing in any magic or technology, you must consider how it would impact the economy and social structure of the world around it.
Anne McCaffrey in her Dragonriders of Pern series did consider the impact of dragons on Pern. And she created a comprehensive believable world for them. If one wishes to see what makes good world building, study this setting.