the short mean answer is if you have to ask, then you're not ready.

Breaking level 50 content up:
Farming Philo (ilv50+ all armor, ilv40+ accessories)
Primals (Ifrit / Garuda) ... (ilv50+ all armor, ilv40+ accessories, ilv50 weapon)
Farming Myth (ilv55+ all armor, ilv55+ Weapon)
Primal (Titan) ... (ilv60 weapon, ilv60+ all armor)
Coil (ilv60~70 armor, ilv70 accessories, ilv80 weapon)