Starting you need a Brim Smith and a Cinder Devil, their innate abilities makes this possible.
Make sure your Brim Smith has enough speed to go first and he will one shot most creatures.

Now that you have a Brim Smith, you need a good weapon.
Make yourself a sword between 150-300 attack (or the best you can, you can always use this on a different kill character later)
Put as many attack stats on it while leveling it up (don't worry about the amount, u can reroll it later).
Make sure you leave one space to put Grant Ability: Strength of the World (put some speed on your weapon as well so you attack first with brim)
Now that you have SotW and enough speed to go first, just attack creatures that don't have special abilities that will stop your one shot of all 6 creatures (one of the 2 middle creatures if your lucky).
If you can have another creature with more speed, it will help removing Shell from one of the middle enemies.

At this point there are many different builds or just your own to go from here on out.
Now that you have a good amount of CP and are closer towards your first nether egg...
GET THE GARGOYLE WITH EX EMBs FIRST (this is HUGE, he will help you finish most rituals, and have enough granite for upgrades)
Pair your creatures abilities with their artifact abilities and other creatures innate/artifact abilities.
Unicorn Vivifier is very good for most builds.
Bone Reaper can keep you from a KO.
Use your first nether egg towards whatever will help you right now (you will get way better ones on further realms)
DON'T make the topaz paragon till you have a team that can easily deal with them.