Have you read HP Babalon's Sermon on color and the aura?
I suggest you do because it is very informative in these matters and will help you enormously in achieving what you want.
Temporal auras come from emotions, these are not the real deal but are like provisional ones that will go away as the emotion goes away.
I imagine that red would be caused by fiery passion or anger.
If you want your aura to become permanently red, work on your base chakra. The most dominant chakra out of your seven chakras will be the dominant color in your aura.
