Earlier today the Croatian national soccer team (I'm an American, that's what we call it) defeated the English team and is going to the World Cup Final against France. As I'm sure many people will be searching in Google before the Final on the 15th, "Where is Croatia".
In most people's minds Croatia exists in the part of the continent that is European but unfamiliar, existing away from the main stage of European countries and using languages that are mashups of different alphabets. So if you're curious about actually trying to remember where any of these countries are and how they fit together, then allow me to try and help.
Map of the Balkan PeninsulaPintrest
The first thing to consider are the basic landmarks you are familiar with. The two most obvious being Italy and the Italian peninsula sitting right next door, and Greece acting as the capstone for the Balkan peninsula, which is the peninsula where most of these countries are. So with your landmarks in mind, start to move out from what you know.
The two countries next to Italy and Greece in the Balkan Peninsula are Slovenia and Macedonia. Both of these countries are easy to mix up as Slovenia is confused for Slovakia and Macedonia is confused for the other similarly shaped countries in the peninsula. I make these two distinct by what I know about them. I follow basketball and the NBA and know that Slovenia just won the Eurobasket tournament last year with two NBA players, have an entertaining living philosopher named Slavoj Žižek, and have a cool looking capital in Ljubljana (loo-blah-nah). As for Macedonia, I have taken an Ancient Greek history class and know about their impact on Ancient Greek civilization (with, you know, Alexander the Great) so I know they must be right next to Greece.
Those are my best examples but you can continue this process to other neighboring countries as you let this gel in your mind for a few days and recall all of this, it all begins to stick. The thing that interests me about Croatia, for example, as someone who likes to look at maps and country borders, is that Croatia slices down the Adriatic Sea and almost makes its neighbor Bosnia and Herzegovina landlocked. I've met people from Bulgaria and Montenegro, I remember hearing about Kosovo back in middle school for some reason, Romania is the only country in the peninsula that speaks a Romance language, Serbia is where World War 1 kicked off, and there has always been this weird assumption around Albanians in movies where they are the toughest bad guys for some reason (see: Taken). And there you go, that's all of Southeast Europe for people who really want to think all these things through.
It's far from the most crucial thing in the world but I have seen and heard from some teacher about the embarrassing lack of geography knowledge most Americans have. It's something I've always had an interest in and this is basically a good way to memorize information in general by making connections both personally and how pieces of information fit together. Or impress people at a cocktail party at your knowledge of this stuff, one way or the other.