Vocabulary has always been a challenge for me. Although I lived in Japan for seven years, I forgot a lot of Japanese vocabulary. I also failed to learn a lot of it. Recently I discovered spaced repetition flash cards, using Anki. (Google "Anki flash cards".) It's open source. It's free. Many people contribute flash card decks. I'm excited!
Print them off and put them in your bathroom. Then you can't escape learning when you need to go to the bathroom ;)
Reviewing Anki flashcards has become my daily ritual before work since I started learning Mandarin! While there is a ton of available flashcards, I've found it most useful to practice with cards I've made myself. And rather than try to memorize a list of vocabulary words--which was really hard for me--I realized inserting new words into a sentence made it easier to remember, and I was also practicing grammar at the same time! For me, Anki works best as translation practice: I give myself an English sentence as a prompt, speak aloud the best translation, and then check my answer. And I don't sit around each day coming up with random sentences, after I had worked through a teach-yourself series, I went through the books a second time and created flashcards for every example sentence given. After I was through with that, I found a really great site that has broken down Mandarin grammar into HSK levels and gives example sentences for each grammatical construction. This has been incredibly helpful! Not sure if there is a Japanese or Italian version out there, but looks like the people who made it just went through grammar books and came up with a bunch of example sentences. Anyway, this method has really helped me. And here is the Mandarin website for anyone else that's interested: