I've started to suspect recently that an important secret of being able to sound natural in conversational Japanese is using a LOT of onomatopoeia words. I've considered mining all of them from jmdict and studying them specifically.
It has great illustrations that quickly get the idea across for Japanese onomatopoeia.
To give an idea of what it is like, here are a couple of example pages: <https://livedoor.blogimg.jp/akky_san/imgs/b/2/b21ad72f.jpg> <https://livedoor.blogimg.jp/akky_san/imgs/3/4/34cf6c82.jpg>
Quite fun to read!
Abbreviation, repetition, and stacking bits of words together are a big difference between natural vs formal Japanese language skills. It's very Lego-like that way.