I learned my first and second foreign language at high school. First one was English and second one German. I want to the U.S. to learn English properly because the English teacher at my school wasn't a really good teacher. Now I am studying both at university. If I need to learn some vocabulary, I use flash cards - Quizlet. I have many American friends here in Prague where I live so I learn also just by talking to them..:) Generally I think reading books in a foreign language helps a lot! Right now reading 1984 by George Orwell in English!
I started learning Spanish, using Duolingo on my phone! It's great for beginners and those who want to learn by themselves! Definitely recommending it!