Step One: Aquire your school's level 48 pet. Mine was colossus:
Step Two: Hatch with another school's pet to get your school's best hybrid. Mine was Sandman:
Step Three: Now you that you have your schools best hybrid, you have to find the hybrid you want and ask to hatch with it. If they respond yes, then once you have hatched your hybrid with the hybrid you want then you have a good chance of getting the hybrid you wish.
NOTE: You will not always get the hybrid you are hoping for. A good tip is to add the owner of the pet you wish to hatch with, that way if you don't get the hybrid you are hoping for you can just ask the person to hatch again :).
I hatched with a Jade Hound hoping for the Jade Hound hybrid. I received this egg:
NOTE: If you too are trying to attempt getting the Jade Hound, the the name of this egg is the Chimerical Egg Hope my guide helped :)
-*The Informational Thaumaturge*