As a rule. I only give to charities or join causes that operate in my country, preferable, in my city. There are a lot of needy people where I live. How can I be expected to help a citizen across the world when I can give a helping hand to a citizen across the street.
In order to be a good man and find happiness, you must first ensure you and yours are well, then your friends, then your neighbors, then the street you live on, then the city, then the country, etc. When there is still trouble where you live, you can't be expected to venture to places you know nothing about and with people you know nothing of.