A quick note on the value of donations
The value you get from money is higher the less money you have. So if you live on $50k a year, $100 is worth much less than if you earn $500 a year.
If you eyeball a map of GPD per capita, then Europe/the US is living on around $50k/year, Latin America is living on $10k a year, and central Africa is living on $1k/year:
But these are averages, so the poorest people in Africa are earning less:
To a first approximation, the value you get from your money is roughly logarithmic. So the value of $100 for someone earning $50k a year is
Δrich = log(50,000 + 100) - log(50,000) = 0.00199…
whereas the value of $100 for someone earning $500 a year is
Δpoor = log(500 + 100) - log(500) = 0.182…
The units are arbitrary, but the gist is that an additional $100 is worth Δpoor/Δrich = 0.182/0.00199 ~90 times as much to someone much poorer.
GiveDirectly does just that: sending money to some of the people to whom it would make the biggest difference. They spend a bit over 10% on delivery costs, have a good reputation amongst people who care about it, and are recommended by GiveWell, the hardcore charity evaluator:
So donations to GiveDirectly are probably a good way to start on the path to making the world a better place, or at least vastly, vastly better than many alternatives. For further resources, see: