Four-syllable words:
akatsuki, inemuri, kaigai, kirisame, kosumosu, sakazuki, shiawase, takitsubo, tenugui, nekutai, matsukaze, misoshiru, monomane, yokohama, rakugaki.
Five-syllable words:
asaborake, iimawashi, ebisugao, emerarudo, oomisoka, kaerimichi, katakiuchi, kirigirisu, kingyosou, shironezumi, sumoutori, sumidagawa, sousenkyo, dairiseki, tsunokakushi, natsuyasumi, hatagashira, fukunokami, hendensho, merikenko, furamenko.
If you can pronounce five-syllable words smoothly, six-syllable or longer words and a simple conversation will not be so difficult. Pronounce each word clearly with the stress on the ending word. This practice actually belongs to the junior level, but starting a little earlier won't hurt.