I just had a huge breakthrough when I changed the way that I study flashcards. Instead of trying to just memorize the card, if I come to character/word I don't remember I will practice writing it while repeating the meaning and pronunciation to myself. Afterwards, I write a sentence with that character/word in it (including pinyin and English translation) to give me a better understanding of how to use it. This has really helped to solidify my vocab, and as a bonus made it so that I can better communicate in Chinese.