Get a friend!

They're saying it all the time. And they're absolutely right - the best way how to master a new language is to have a native speaker as a friend. But when I say friend, I really mean a friend. Because only then you will really communicate on daily basis and sooner or later you will probably cover every thinkable topic in the Universe. Yes, you can chat with native speakers from time to time but what you really need is a total immersion and that is possible only when some friendly feelings are involved.
There is the trick - in a friendly chat, native speakers use whatever expression come to their mind, just as you when you're chatting with your BFF you've known since your first grades. Often it will be slang and the more experienced you will get, the less help and explanations you will need from your friends when they use some word/phrase you don't know. What more - it is no shame to ask your friend - "What does this mean?" - "What do you mean by that?", but I would probably not be as courageous with some casual acquaintance. It is also great to meet both in person and on chat, as when chatting, you can look up the phrases by yourselves and even add it to your personal word list. Also, you will probably better remember the word or phrase because it is placed in a very specific, personal context and it carries a message only for you.
When looking up new words and phrases, I find the web site Urban Dictionary very useful. They also have a great FB page where they post new words and phrases daily - and most of them are pretty amusing! With these, you can easily astonish your native speaker friends ;-). It is also important to remember that we are all just humans and even native speakers can have something wrong. Bear in mind from that background your friend is and apply the new knowledge wisely and approrpiatelly. There is nothing easier than ask - "Is this considered polite?" or "Can I use this when speaking to my teacher/boss?" This info is often not involved in the dictionaries and you never know what faux-pas you may cause by wrong expression.
Well, is sounds quite amazing, doesn't it? I am not saying that with a native speaker as a friend you can throw your textbooks aways and that you can spend the money put aside for language courses on hot-tub full of champagne, but having English/American/Canadian/Australian/New Zealandian/whatever friend can be an invaluable addition to your language learning. And where can you meet native speakers? Well, this we will discuss later on.
So long, folks! :-)