Everyone knows that one of the best ways to really learn a language and achieve a high level of fluency is to actually go to the country where the target language is spoken for a full language immersion experience. If you are learning French then go to France, if you are learning Spanish then go and spend some time in Spain and if you are learning something really exotic (for a westerner at least) like Mandarin then China beckons with all its many wonders.
Whichever language you are learning you will eventually want to spend some time in foreign lands to fully immerse in the language and culture. It is a fantastic experience and really helps to not only improve your fluency but also it reinforces the decision you first took to start learning another language, when you are actually there talking to the locals and making new friends and seeing all your hard work and months of study suddenly coming to life.
There really is nothing better than being there in the thick of it to give your language skills a major boost and reach the next level of functional fluency.