Have you come across 形声文字 in Japanese? Looking for examples and language tips

I was recently reminded that Japanese kanji are not always trying to ruin my life. 

Sometimes, they actually give you a hint. Also, any other language-learning shortcuts you’ve found especially helpful for Japanese?

Lately, class content has largely been speed reading (速読) practices on yomikata, meaning and comprehension/summary.  During this, my teacher explained one useful way of reading words, that has since helped avoid lamentably frequent mistakes during these readings under pressure.

Take 健 and 建 (from 再建 and 健康). Both have the same けん reading, and it turns out 健 borrows it from 建, since 建 is sitting on the right-hand side. Or 適 and 摘 (from 適当 and 指摘). Both read てき because of that neat little 啇 piece. And 稿, which has 高 sitting there politely saying “read me as こう.” (from 投稿 and 最高)

Apparently, these are called 形声文字, where one part hints at meaning and the other part hands you the reading. My まだまだわからない self finds this oddly generous for kanji.

As I don’t fully understand this, I wonder whether there’s a stronger clarification out there please. I still stumble into pairs where the right-hand radical looks like it should help, but then doesn’t. (see 規模 and 縞模様, I think?) 

I’m curious: have you noticed other examples of 形声文字 in your own studies? Are there particular right-side parts that reliably give the on’yomi, or is it more of a case-by-case thing?

Also, any other language-learning shortcuts you’ve found especially helpful for Japanese? I’m entirely okay to brute-forcing a lot of vocabulary, but I’d love to know if there are smarter ways people approach this.

by neworleans-