my advice: disguise your intent. Act like you belong. Look like a tourist. People don't give two fucks about tourists. Don't make eye contact with your subjects, stare past them as if you were taking in the scene. Squint and grimace through the viewfinder as if you were trying to figure out your camera. They'll get embarrassed and move on.
What happens is that you get out there trying to fill this mental picture you have of the sneaky street photographer, which ironically just makes you look extra conspicuous and suspicious. Take pictures brazenly, proudly, and people will ironically ignore you.
There's a good documentary about Daido Moriyama that follows him around while he's shooting street photos. He just kind of casually walks around and snaps photos, but it's Daido fucking Moriyama. You know that he's getting some interesting photos, and he's doing it with a film crew tagging along, probably three extra guys. And yet no one pays attention to him, because he acts like he belongs. It's about becoming so visible that you become invisible. https://youtu.be/1O7mZE4xY1E?t=1017