My experience with vocabulary building has been to read as much as possible,
right from the beginning. For instance, reading "Jip en Janneke" can enrich your
basic vocabulary by about 300 words. Once you graduate beyond children's books,
you find your vocabulary growing really quickly if you continue to read adult
books diligently. That combined with practice conversation with someone who will
give you corrections is what finally made the difference for me. Nu kan ik wel
een echt Nederlandse conversatie hebben met iemand!