The most beneficial way to maximize your gold is to optimize your mix of dragon habitats. You’ll want to load up on the habitats that earn you the most maximum gold, such as the earth habitats,, and then fill them up with dragons (especially hybrids, which earn you more gold per hour). Level up the dragons to earn more gold per hour, as well. And of course, maximize the total of habitats that you have. The higher your experience level, the more habitats that you can have at the same time.
Log back into the game every day, even if you don’t plan to play that day. The rewards for logging in daily include free gold and free crystals, and the more days in a row that you log into the game, the higher the rewards will be for logging in. If you don’t log in one day, the rewards will reset themselves.
Complete the quests to load up on free gold and free crystals (depending on the quest in question). Check the quests menu to see what rewards each particular quest will earn you. Most of them will include gold. Some of them (less than the gold-earners) will also earn you free Crystals, such as logging onto Facebook and adding more friends in the game. If you are having trouble finding Facebook friends who play, look in the App Store review pages, the game’s Facebook page or the comment section of this article or post your own info if you so choose to.
Complete an entire tier of battle in the battle area in order to earn rewards as well. Tier 1 will earn you three free crystals. The higher the tier that you complete, the more crystals that you will earn as a reward. Of course, the dragons get tougher and tougher, though, so keep using food to level up your dragons and take home the victory in battle.
Finally, you can earn free Crystals from clearing out one of the elemental obstacles (the ones which take three dragons of a certain type to complete). Free gold and crystals can both be earned from the Elemental Chest every time that it flies by.