Look into Chakras alot of the things I learned about auras is from my studies of chakras and subtle energies. If you have any further questions. I will be happy to assist.
From personal experiences:
Most auras are seen to have an egg like shape but not everyone sees aura the same. Many of us will see auras into multiple colors like a painting. Others will just see one aura. Some might see auras in black and white. Others can sense auras through other means such as scent, vibrations and perhaps even more.