Small, Fine, Trivial
い adjective
こまかい
じゃあ、このキャベツを細かくきざんでください。
Then, finely chop this cabbage please.
細かいお金しかありません。
I only have small change.
木を見て森を見ず、だぜ。細かいことにばかり気をとられずに、もっと大きいスケールで物を考えてくれよ。
You can’t see the wood for the trees. Don’t just focus on the details, look at the bigger picture.
Remember 細い and how it means "thin." Well, this is another adjective that comes from the kanji 細 with a similar but different meaning (sorry!). If you think about something that's very thin, though, there isn't much surface area. In order to use this very thin thing (say, to put your favorite model railroad on) you have to zoom way in and get incredibly detailed with it. It's super small and fine, so get your magnifying lens out! You can remember that this one is "detailed" or "fine" because the かい makes you think of coyotes. You put a ton of work into this detailed and fine model railroad on a very thin piece of land. Then, a coyote comes in and trashes it all, because you made the mistake of making it out of meat.
This word has a different reading from the ones you've learned so far (sorry), so here's a mnemonic to help you:
After the coyote wrecks your pretty train things he bites you on the head, sending you into an indefinite coma (こま).