This is AWESOME advice. I have no problem hitting up tourist spots but they can be a bit much (and sometimes hugely overrated). I try to balance those out with just living in the city eating and drinking away from all the popular spots too.
If the place you’re visiting has good public transit, I’ve also found that I strangely enjoy riding trains and buses to random places. It’s a good way to immerse yourself and get off the beaten path.
Great point about making sure places are actually open when you want to go. I think I’ve taken it for granted that a large majority of the places and things I typically want to see have regular-ish business hours or are open 24/7 (e.g., something in a park or other public space).