The mnemonics that work better for me are the ones in Japanese.
For example, instead of using Koichi (sorry) I have in my head a big family of words that are read こう with the on reading.
High, school, go, mouth, construction…
This does not work very often with the kun reading, but I already know it for many kanji since I am not new to learning Japanese.
Sometimes I break down a word I already know, like みんな, everybody… and I used it to learn the reading of 民. Peoples and everybody are similar concepts.
What methods do you find useful to build your own mnemonics?