Back when I used to fly small planes, one of the aviation magazines had a monthly article: “I learned about flying from that” – all about mistakes made while flying (survived!) that taught important lessons.
I recently dusted off an amateur radio project that I put on the shelf 2 years ago because it was not working out as I’d planned. Oh, the mistakes –
BS170P in an ‘E-Line package’ that is not *quite* a BS170 – pins were flipped (D-S-G became G-S-D … no worky!).
No ground to one of the boards – schematic said it was inbound on a cable, but PCB had left it off.
No ground on that PCB carried down to an LM386 speaker output that I’d built, causing all havoc there – Horrible BUZZZZZ.
That radio works now! Patience (sometimes the patience of Job) and re-reading and double-, and triple-checking, and trying alternatives… that’s what works.