For higher-level students the most efficient way to study intensively is one-on-one with a qualified teacher. My Chinese teacher at TailorMade was excellent. She was helpful, skilled at teaching Chinese to non-native speakers, and (necessarily) patient with me. Outside of class hours she was even working on researching materials that would match my study interests. One-on-one with such a skilled teacher, all on a custom schedule is impossible to beat at this price.