Everyone has the ability to see auras. It is whether the person chooses to learn or keep the abilitiy which we are all given. Some say the aura seeing is from teh Anja. Wether this is true or not I am unsure. But I do offer help with people wishing to see auras or understand them better.
Concentrate on your friend who is a little far from you. Concentrate from your eyes for his head. Imagine there is line glowing from his head. Concentrate harder and harder like a telescope zooming towards the object. Pratice pratice then you may see others aura.
As said above there are some exercises to develop the skill of sensing / seeing auras. Your aura is the electromagnetic field of energy surrounding your body and forms your personal energy space. This is a natural thing, and also the ability to see / sense it is nothing extraordinary or impossible.
Here's a good article about seeing and sensing auras:
Later, after you get into some techniques of seeing auras, practice for some period and develop your skills I'd advice you to take the next step and learn reading the auras you see. You may find this article as very informative and helpful for this:
But please remember to be patient with this. In some cases, it may take years of practice and study before a person is able to see the entire aura and all of its intricacies and components. But any person can begin to detect slight indications of the energy field with little effort, and usually in a matter of minutes if they can attain and maintain the correct brain state. You must be willing to meditate in order to see auras. You may find other articles that interest you about this subject...