The Africans are generally gentle and accepting people, and not much will upset them, although I encourage appropriate dress in their presence. In the Muslim areas around the coastal areas, women should wear skirts and cover their shoulders when in town. There is often a large economic difference between you and the people you visit, so leave your expensive jewelry and watches at home, and be careful not to pull out large wads of money when paying for something small.
Before photographing local people, I recommend you first spend a little time with them. Some tribes consider that a photo takes away their soul… though for a few dollars that same soul can make a speedy return! Always ask permission before putting your lens in their faces! We all appreciate such courtesy!