Just memorize them in a way that make sense to you. I remember the Oceanic countries in pairs or threes, like Vanuatu and Tuvalu (because both have two U's in their name), Kiribati and Nauru (because they are next to each other), etc. As long as it makes sense to you, it's good. Some of the mnemonics I have for remembering some of the tiny countries are pretty stupid, but they work.
Adam Stewart
135
Brayden Peterson
149. Could have got a few more if I didn't have work in 10 mins
Robert Baker
Do you do things half-assed and then offer gay excuses for yourself when you're at work, too?
Benjamin Hill
Probably better than me. I know a lot of these places, but I always blank on names and dates super hard. Doesn't help that I forget how to spell half of the names properly.
Even ignoring that there's always a lot of places that I have trouble remembering in general.
Sorry to anyone who's country I forgot about. I should do better.