Arguably, just to leave them alone, neither exploiting nor trying to "help". It sucks and it hurts, but outside interference does not seem to help a society heal itself. This has been argued by more informed people than myself-- https://www.uvm.edu/~jashman/CDAE195_ESCI375/To%20Hell%20wit...
That’s true in order to truly change a society you have to no longer be an outsider, but that’s a level of entanglement that NGOs rarely do now adays.
The ones that do it though are all religious institutions so their goals are more social/moral rather than economic or geopolitical.
Have you seen how active China and to some degree Russia have been in Africa? When there is vacuum someone will fill it.
https://news.ycombinator.com/item?id=47978386
What would help is to buy their products and resources for a fair price.
How do you determine what's a fair price?
Sometimes it's hard but with things like gold it's pretty obvious.
Who's currently getting a below-market deal on gold from Africa?