How can I improve my understanding of spoken French?

If you're planning on spending some time in France - and with the French, understanding spoken French is essential. Thankfully, there are not nearly as many accents in France as there are in the English-Speaking World. That being said, if the Quebecois accent is the strongest I know, there are also some pretty strong ones in France, take for instance Marseille and the South-East region. The other main ones would be the Northern accent, the Alsacian, and the South-West accent. People from Paris like to believe their accent is "neutre", but other regions strongly disagree. One other obstacle could be that the words used by other young people (and even some older ones) never made their way to your textbooks. Due to various slangs, the language spoken by young people is not easy to understand for foreigners (and for their parents, which is the whole idea behind this). For instance the "verlan" confusingly deconstructs syllables of a word and puts them back together in alternative order. The most common ones for instance are "relou" (from "lourd"), "ouf" (from "fou"), "meuf" (from "femme")... Verlan is a staple of conversations among young French.

All these difficulties can be overcome thanks to simple and enjoyable methods: I recommend watching as many movies and series you can find (Netflix has some great ones, and I'd be happy to recommend some). To really identify what is being said, watching with French subtitles on is really helpful, and you're still improving. Finding some recent music you like in French, and having a look at the lyrics can also help a lot. All this will be a great preparation if you want to face French people, who will also teach you some of their own slang or accents.