As previously mentioned, South Africa is real good, ATC, airspace, etc. For the rest... don't rely too much on services (or lack of...) make sure you know where the other traffic is at all times even when under control, don't expect ground navaids to work, be smart with fuel, and then add another 1000 kg! Check and crosscheck payload, as many ended up taking off with much more than they would have hoped.
If you make stops at secondary airports, you might want to call first, just to be sure they have fuel...
Bring a whole bag of pens, pencils, key chains, stickers, pins, whatever, it's always nice for people on some hard places to get a little present, it may come handy if you stop at numerous places.
And smile! I spent many years in Central and West Africa, things get always easier with a smile and a nice word.
Flex