location
one of the first things you look at when you start a new game is the buildings / signs. with out going into what will be explained in the other parts you get a general feel for where you are quickly. its fairly clear the differance between Euroupe and the United States but you can generally get a feel even between Australlia and New Zealand. just the way they use words slightly differantly or maybe it's the acratechture. it could even just be that you see a flag thet you know. most places are just like this.
language
the language of a place seems obvius however there's a lot of languages that it can be hard to know them all.
There are a few basic things you can do. The first thing I would recomend doing is learn the type of text they use.
A good example is Cyrillic verses Latin script
If you're still having issues try finding distinct charecters or words that would give clues as to what language it could be. a good example of that would be like the polish Ł or another letter with a accent. another thing that could help is if you say it outloud and try to figure out what it sounds like. this sounds dumb but it can really help.
other clues
their all all sorts of things that can help to give away where a place is. one thing that comes in more then you'd think are licence plates. most places have uniqe licence plates and they can really help with narrowing down where you could be. For example if you are in europe you will always have a wider licence plate with a blue badge on the left.
Some common thing you should look for are domain names. there is a domain name for every country and state so if you find one of them it could be reall helpfull. there's too many to list all of them but most of them are self explanitory. one of the ones that don't make sense is .de being for germany but for most of them you just have to memorize.
geography
Geography is something that you might think would be obvious but in reality when I play I often ignore the geography and go with a bit more of an outlandishy guess. most of the time its you don't even really have to think about it. if you're on the coast you're not going to guess kanssas. you cant really explain how to tell the differances between the forests in finland versus the forests in siberia, it's mostly something that you just have to learn with time.