In the past two years, I have moved to two different countries where my first language (English) isn't spoken.
In the beginning, you can get by with speaking English or communicating with actions, but eventually you will realise that you need to learn the native language of the country if you are going to really live in that country and culture. So, when people ask me, "how did you learn to speak five languages?", I simply reply, "Be social!"
Of course it is necessary to get a basic understanding of the grammar and structure of a language, but you cannot learn a language without being social.
Get Out of your Comfort Zone
What exactly does this entail? Frankly, it means you have to get out of your comfort zone and start chatting with native speakers of the language you are hoping to learn, and with locals from your immediate area. You really need to be enthusiastic, curious, and persistent about starting conversations and making an effort to get to know a new person everyday.
That means every time you go to the supermarket, hairdresser, restaurant, or gym, make an effort to learn new words by interacting with the local people. Nowadays, Google is a great tool and makes it even easier for us - if we're really stuck with a word or phrase, we can just look it up on Google translate.
Socialising forces us to make an effort of remembering new words too. By being social, you experience the pressure of potential embarrassment if you mess up, and it's not a bad thing to be a little embarrassed in the beginning stages of learning a language. Of course you won't get everything perfect the first time, but don't let that stop you. Keep up your enthusiasm for learning new words and vocabulary!
Your listening skills can only develop in social environments. By keeping a social lifestyle, you will pick up new words from different people and the most important words will become apparent to you. Your vocabulary will start building with these words which you find are commonly used. Slowly, from there you will identify more words and your vocabulary will build.
Before you know it, you will be ordering a meal in that language and maybe even making small talk with people at the gym. These might seem like baby steps, but don't underestimate your progress even if it seems slow. It's all about keeping your social lifestyle consistent with native speakers, and really making an effort to learn new words and make new friends!