There are those that believe that we live in a zero-sum world, that is to say, a world in which there is a limited amount of good stuff, and thereby the object of the game is to get as much as you can of the good stuff, and hence the devil takes the hindmost. This type of selfishness is created by the false belief that there is a limited amount of good stuff in the first place, but in actuality the limits placed on mankind, are the limits of his imagination, his skills, his throughput, his efforts, and his teamwork, so that limits that are imposed, are self-imposed, and a zero-sum world view is wrong, for the sum of all its parts will either grow or even shrink, depending upon how mankind cooperates or not with one another.
Certainly, the first issue that must be considered is the mindset that each of us has, in which, fair to say, those that have troubling or selfish mindsets, probably aren't going to be doing or thinking the things that makes the world better for them having been here. That is to say, wrong thinking, leads to wrong actions, though truth be told, because we are gifted with free will, we are therefore free to choose what to do or not to do, but recognize that the corollary of free will, is that we must surely reap what we sow, for better or for worse. After all, it is pure folly to believe that what we do and how we act, does not have consequences especially for those that we deal with on a daily basis, of which, while we cannot control what others actually do or don't do, we have a responsibility to recognize that our interactions with others have influence upon them, for good or for evil. This means, in recognition of such that we should want to behave in such a manner that we provide a benefit for others, and not a hindrance, for in having done right we are doing our part to increase enlightenment, as opposed to darkness and ignorance.
So too, recognize the logic that if each person in their own way, is helping to make the world a better place for their being here, than that world will bit by bit, step by step, good act by good act, will become that better place. The type of change that so many profess that they want, cannot happen overnight, for it starts in the hearts of mankind, then their actions, then their persistence, then their caring, and then their love, in which, all that, put together, consistently, will result in a better world. For if the world is not made in the image that you wish that it was the fault is most definitely not in the stars, but in us. No doubt, most people will proclaim that they lack the power or the influence to affect change, which is only true in the sense that they lack some powerful magic wand, but that isn't what we need to worry about, what we need to worry about and concentrate upon is the people that we deal with day-by-day, in which, we must endeavor to do right by these people, in things big and small, every single day.
Endeavor to make the world a better place by beginning with yourself, so as to better yourself and then endeavor to help others as you can to be better themselves. Do this, and your life and this world will be better for you having done so.