Situational awareness over Africa (while in cruise) is something that dog-tired crew sometimes let slip. ATC will be of little assistance at the best of times, and will have NO idea if anything non-standard occurs as the language barrier is huge. We all duck around weather without (sometimes) even informing the irritation on HF that we loosely refer to as ATC, and thus have to have a firm picture of weather, traffic, adjacent airways, terrain etc.
We frequently end up talking to no-one except ourselves, and as Billy says, thank goodness for the requirements for the introduction of RVSM...
Review collision avoidance procedures in the IFBP area as detailed in the Jepp text pages (different to that detailed for oceanic areas), drink lots of coffee and make the 126.9 events part of the crew's IFE. Play a game called "I know who's lights those are that's approaching" as opposed to "who the hell is that?"