I usually have a look at Google Maps for what’s around me and check the reviews.
However if I see a restaurant with a lot of tourists I don’t go
I usually look for the busy restaurants where only locals eat, also places outside of busy touristic areas
if i’m traveling on business I usually have to urge my coworkers to take me where the “normal people” eat… lol. they often opt to go to more fancier places, which are usually a let down. My first trip to Taipei about 10 years ago we were eating all sorts of fancy stuff and I was pretty unimpressed, then the last day our colleague, in a rush to get to meetings later that day, just took us to Din Tai Feng (which of course now is insanely popular around the globe). Immediately I was like… “what is this!!! how have we not been going here the entire time!!!” lol
In Asia, the smaller night markets are great aren’t they. In Taipei for example I typically avoid Shilin having been once (too touristy).
The smaller ones tend to hit better.
In Europe (for example when I’ve been alone in Italy), always Osteria/Trattoria, as I’m sure you’ll agree @Ottavia-Mandarin_Simplified_HS you know you’re going to get something true and local at these little gems
If you plan to go to Vietnam, my advice is to just look up on TikTok bc the local food here they don’t actually put it on the map, so usually if you check on the map, it’s more likely for you to find a tourisy place. But however, if you go to Seoul or Korea, just use Naver Map and type 근처맛집 (good place to eat around here), and go for the most reviewed ones, usually are the best ones ever!!!