The ability to perceive the emotional state of others, empathy, is a natural mechanism evolved in the thinking of humans [5]. Research has demonstrated that empathy has both a relationship with prosocial behaviors (actions taken for the benefit of others), as well as a negative correlation with aggression [2]. So imagine then, if every one of us became just a little bit more empathetic than we are right now; what impact might this have on a larger scale? Moreover, if an individual does desire to become more naturally empathetic, how do they actually go about changing their ingrained thinking, to achieve this? This page shares one approach for attempting this: a very simple thought exercise which takes no more than a few minutes each day, which aims not to refine a person's ability to empathize, but to generalize the scope of scenarios which cause them to empathize, by challenging them to continually identify situations in which they have no reason or inclination to empathize in and then, periodically and randomly, to empathize in those situations, even if it feels unnecessary or absurd to do so. Anecdotally, this exercise caused a profound (and lasting) change in how I empathize, and as a result, how I treat others. While I have no way to know if performing this exercise could have a similar impact on anyone else, I like to share it in case it might.

Empathy Briefly Defined: Affective vs. Cognitive Empathy

Empathy is the ability to understand what another being is experiencing, from within their frame of reference. One form of empathy is the emotional response that arises from witnessing another's emotions, in such a way that our own emotions mirror what we are witnessing. Suddenly, and without effort, it is as though we feel the other person's pain, or their joy, etc. Empathy of this type is known as affective empathy, or emotional empathy [4]. Here are some examples of affective empathy:

Humans can make the conscious decision to empathize, too. This other type of empathy is often referred to as cognitive empathy, or colloquially as "picturing yourself in someone else's shoes" [1]. Cognitive empathy involves two components:

The "Empathy Exercise"

You can go ahead and skip directly to the exercise if you'd like, which is highlighted below. However, I think it will be more effective, to first devote a bit of thought to the following two points:
The Empathy Exercise: Do the following for one month: When you encounter others, ask yourself this question: Is this a situation that would normally cause me to empathize? or, alternatively: Am I, (at this moment), empathizing with the individual(s) I am encountering/interacting with? About once an hour, at random points throughout the day, when the answer to that question is 'no', devote a few moments - 10 or 15 seconds - to cognitively empathizing with the individual(s) you are encountering.

An example: Here is an example from my own experience with this exercise. These are a few situations I began identifying, that I was not having a natural inclination to empathize in, and so began empathizing in randomly: driving to work (towards others drivers); reading generic business emails from executives in my company (towards those executives); heated ethical debates (towards those I was debating/disagreeing with); routine, emotionally neutral interactions with strangers such as buying groceries. As for what I did in those moments, I'd take a few seconds and imagine what that other person was experiencing. (Were they frustrated, stuck in traffic? Bored at their job? Angry/confused that I was disagreeing with viewpoints obvious to them?) I'd imagine moments of joy in their lives, and moments of sadness. I'd imagine mundane aspects of their lives (making breakfast, doing taxes...) Since there was no reason to empathize in these moments, doing so did feel odd and unnatural at first. But (very quickly) it led to some dramatic shifts in how I viewed those around me, and as a result, how I treated them. Furthermore, because the situations/targets of empathizing were random, the perspective shift was a general one, rather than being limited to specific individuals or groups. Rather than bias you by explaining the changes I experienced, discover what (if any) impact it has for you (if you'd like to try it out that is). Best wishes!

References:
[1] Batson, Daniel C. (2010). Altruism in Humans (Chapter 2). Retrieved from: http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195341065.001.0001/acprof-9780195341065-chapter-2
[2] Eisenberg, Nancy. (1987). The Relation of Empathy to Prosocial and Related Behaviors. Retrieved from: https://www.researchgate.net/
[3] Håkansso, Jakob. (2003). Exploring the phenomenon of empathy (Doctoral dissertation, Stockholm University), pp. 21-25. Retrieved from: http://www.emotionalcompetency.com/papers/empathydissertation.pdf
[4] Hoffman, Martin L. (Cambridge University Press, 2000). Empathy and Moral Development: Implications for Caring and Justice, pp. 29-30.
[5] Links, Living. (2008, Jan.). Putting the Altruism Back into Altruism: The Evolution of Empathy. Retrieved from http://www.annualreviews.org/doi/abs/10.1146/annurev.psych.59.103006.093625?journalCode=psych