For people who are looking to get into dragcave, here's a resource post:

Dragons are more likely to get sick if you put them up for viewing when they're 6 days or older. It's safest to wait until a dragon is about 6 days old or younger to put them in threads or hatcheries. If dragons get sick, they can die. Sickness is caused by having too many views too quickly, so also be careful how many hatcheries you put them in!

Eggs only hatch at 4 days and younger. Hatchies only grow up at 4 days or younger.

Red and pink dragons are very useful. Reds decrease the amount of time left on a dragon egg. Pinks can set the gender of your dragon, based on the gender of the pink. If you plan on breeding, purple dragons can increase fertility of dragons and thus their likelihood of breeding. And aeons can predict the gender of a baby. Get your hands on a few magi dragons too because trading is important.

Certain dragons are more valuable than others. Generally these are "rare" dragons; first generation/cave born gold, silver, copper are especially coveted, but so are early generation prizes. It's hard to catch golds and silvers (I've only ever caught one silver and I got my golds from the market and trading)

If you want to get your trophies fast, a helpful strategy is to hunt down rare dragons and then trade them for hatchlings. You can hold 3x as many hatchies as you can eggs, so if you're lucky you can build a scroll pretty fast. You don't HAVE to do this, though; I didn't, I just know it's a good strategy to get Platinum as fast as possible.

The cave refreshes every 5 minutes on minutes divisible by 5.

You can check what kind of lunar heralds are dropping on the Market Page. Also to build your market page, you can lurk hatcheries and click on eggs that you need. This is how I built my dino collection.