Your aura is a reflection of your health, energy, and emotions.
Take care of yourself, Vepper. Eat foods that are good for you, be at least somewhat active, and just stay healthy; that will give your aura a healthier glow.
Also by keeping your chakras clean, and well balanced you will notice helps this process. You chakras generate energy that often times effect your emotions and overall mood. Balancing your chakras will tend to make you a balanced person.
A happy body is a healthy body-- which has a strong, healthy aura.