practice and more practice. find some friends who share common desire in learning language like you do and routinely practice with them. once you get used to speaking or writing in your desired language regularly, the process of improving more advanced skills will happen more smoothly I guess. another tip that works on me is this: watching movies. the best thing about it is you can learn something in such a fun way. I've been watching some american tv series with english for a while now. it really helps developing new words and idioms vocabulary. most importanly, it helps you UNDERSTAND those words by showing you how to use it in proper context, good luck! :)

My friend who became fluent in Spanish as a second language as an adult said that conversation was the biggest factor. Learning to use language in an unscripted and spontaneous way every day (he was in Honduras for two years) cannot be replaced.