You need mnemonics to learn with rapid success. It doesn't have to be anything clever, just an alternative way of retrieving the information that your brain might be blocking.
For example I remember Slovenia, Croatia, Bosnia & Herzegovina and Montenegro from "slo cro bo mo".
I assure you that if you invest two hours into any of those maps (expect World/Oceania), you can score above 90%.
Maybe I should've put this into OP idk...