Vials
In the game, players use vials to extract DNA for breeding their creatures. Use the three-star vials rather than the two-star ones. They work more efficiently though they cost more to use. Click and drag empty vials from the inventory to the animal you want to extract the DNA from. Use the "Eggcelerators" later in the game with higher-tier monsters. "Eggcelerators" hatch your eggs immediately but cost 100 tokens. The higher-tier creatures can take over 20 hours to hatch, so it is best to wait and use the "Eggcelerators" for them.
Raptor
Breed a lizard with a bird to form a raptor. Name the offspring with a generation number. For example, after the initial breeding of a lizard and a bird, call it number "2." Breed this second generation with either a bird or lizard. Take the third generation and mix it with either a bird or a lizard again. The fourth generation is a raptor. Never mix two animals from the same family, such as a lizard and a lizard.
Spider
A wolf and a moth in the game form a spider. It is not an ordinary spider but a giant one with a scorpion tail and insect wings. Breed the second generation with either a moth or a wolf. Repeat the breeding with a moth or wolf again and the fourth generation is the monster spider.
Crocodile
Breed a lizard with a crustacean to form a crocodile. Its offspring is either a lizard or a crustacean. Mix the second generation with another lizard or another crustacean. With this process of mixing every generation with a lizard or a crustacean, the sixth generation creates the crocodile. To make a dragon, a crocodile is bred with a raptor.
Money
After you tire of breeding and fighting your monsters, take some quests. Near the airport, you can opt for safaris, such as "The Everglades" or "Black Forest." Quests start at low-levels earning little money, but soon they increase your pay and skill level points. After 50 kills with your creatures, you can also enter a parallel universe.