The best thing, in my opinion, that we can do to make the world better is to reduce our consumption of animal products. Humanity has made incredible advances. Another impressive advance would be to maintain our high quality of life, while reducing the suffering caused to the vast majority of living beings on the planet - those in the human food industry. The current demand for animal products makes this almost impossible. We are creatures of habit. Practicing consideration towards animals will manifest in relations between humans. Stated negatively, there will not be peace between humans when their lifestyle is based on massive suffering and violence. Many now believe that a plant based diet is healthier and better for the planet. Checkout this talk (has Hebrew subtitles). You might appreciate this less `militant' talk by Neil Barnard. Check out this one which made eating vegan much simpler for me. At least watch the short one where Bill Clinton talks about becoming vegan!
p.s.- It is common to think being vegetarian is the natural intermediate step, but now I think it is better to start with cutting out dairy. It has a similar ethical advantage. Health-wise, while some people (especially young women) seem to have problems with cutting out meat, everybody I have encountered, myself included, has benefited from cutting out dairy.
p.p.s- I know how challenging it is to be Vegan today - I do not adhere 100% myself. If you identify with the subject, just start small - any reduction in consumption of animal products is great. In this context, watch this TED talk about the weekday veg.
As someone who has tried a lot of meditations\therapies, the one thing I have found which I believe gives a true solution to the basic problems of human life - sorrow, loss, physical pain, ect. is Vipassana meditation as taught by S. N. Goenka, There are free courses all other the world.