Im learning English. I did order only one new word per day but i almost forget it after 3 or 4 months later.
Do you have any experience in increasing the vocabulary quickly without forgetting?
USE it! Use the vocabulary you learn - that's the easiest and best way to keep it in your mind.
There is a universal receipt: read books/articles (Breaking News English is awesome) on your target language, listen to the broadcasts, find a language partner and tell him what happens in your life.