i'm guessing your third eye would be involved, since most psychics can see them without trouble. i've never been able to see colour, but i have been able to see aura's. try holding your hand up and stare past it. this usually works best when you stare at a dark coloured wall, you should see a line of light surrounding your hand. just relax, don't look too much at your hand, and it'll come to you. colours however i can't help you, i only see aura's, no colour.
I personally started seeing auras after wearing my Amethyst and celestite necklaces. I do not know if wearing them caused it somehow, but it would not hurt to try. Both of them are said to help balance your energy, connect you spiritually with the divine, and stimulate your third eye. I hope this helps :)
What huggy said is deffiantly true, I used to have major headaches all the time, then when I bought an peice of Amethyst to massage my third eye point, I stopped getting them and found out doing so had also caused my third eye to be open about 20% more.
Wether or not your third eye being open helps with seeing auras though, idk. I once read online about how to see auras by staring at the outline of your hand and that you should be able to see it. So I started doing that and can pretty much see mine with only a few seconds concentration now. I can rarely see others from a distance, though I have once before. And can almost never see colors for some reason.
Even before I knew magick was real, in my childhood I always saw auras of many times and of many colors. An aura looks like a fuzzy outline emerging from a person, animal, plant, or object's body. By what color the aura is tends to show how the person is feeling at the time. Yet objects (from what i've witnessed) simply and plainly give off a white aura continuously. I've noticed auras mainly while attending school and looking upon my teachers, feeling their auras. For me I never opened my third eye yet, I simply stared at one place for a while and had my eyes get naturally in and out of focus's balance. And possibly up to half a minute later i'll start seeing auras. (Sometimes it gets so powerful that I start seeing the aura of everything, the sky, the earth, the wind..)