Does aid to Africa do more harm than good?

The way it's being carried out now, yes. While people may have good intentions with it, sending them supplies, food, and tech and stuff does very little good. It doesn't teach them to be self-reliant and learn how to do this stuff on their own, and second, a lot of crime lords and governments over there will often just seize it anyways.

The two best ways we can help them are as follows:
1) Teach them how to rebel against their current tyrannical governments
2) Teach them how to create modern technology and agriculture.

What we're doing now is essentially just causing the ones in power to be wealthier since they just seize anything we send them. Giving the people knowledge, however, cannot be seized.

Charity does have the inherent issue that it dis-incentivises people from learning to be self-reliant. Dependency on someone or something, while able to increase one's productivity, also creates a problem in that the one loses the ability to control their own future - and once the entity they depend on is taken away, their entire world crumbles.

That said, certain forms of charity are much more likely to lead to the positive outcome, than others. Recall the saying: "If you want to feed a man for a day, give him fish. If you want to feed a man for a lifetime, give him a fishing pole".

Bill Gates chooses the right approach here: he founds and funds African schools, hospitals and cheap IT technology. He invests in human capital, so, instead of consuming, people learn to produce. Then those people will take positions in the African governments and push them towards reformation, based on the knowledge they have acquired. The former colonies can follow the footsteps of developed nation and, eventually, themselves become developed.

In my opinion, I believe that we should set up more trade deals with African countries rather than just giving them money. I believe this because it will help their economy in the long run as African countries will learn how to run businesses and increase their GDP (which is better than just relying on places like the UK or US because they need to learn to be independent).