Most auras you see have 3 layers of color, with one color being the dominant. It has been said that they represent the physical, spiritual, and emotional well being of the person. Variation in the aura of a person could be warning of an illness in that area of the body. While murky, unattractive colors in the spiritual aura could be the result of negative karma. Once the trouble areas have been established, meditation, visualization, and inner rebuilding should be done to correct the problems.
The best way to describe energy patterns would be a clear pulsing radiation from an object or area. Intense places of energy usually have a high amount of energy that radiates whether seen or just felt.
Esoteric energy is usually caused by past objects or persons in an area that have left the energy mark upon that area. For instance, if you look out the corner of your eye and think you saw something but look again and it's gone...this may be left over energy from the past, not just your imagination.
Here is an exercise to get you started:
Relax your mind completely and then relax your eyes by defocusing them. This is kind of like staring off into space. Allow your eyes to continue being relaxed and allow your mind to receive the images. With a piece of plain white paper, place a penny on top of it in the center. Try to determine the aura of the penny(usually green). This is one of the reasons we use green in money spells. If you find you can't do it still, continue to practice and don't forget to blink!