Never been to Tokyo. My approach in the past had been to either: 

- follow the people. See a group of people having fun? Follow them to see where they heading. See people cuing to enter somewhere? It’s likely to be worth it. 

- follow the music (or find it). Live music is best, I’ve always met ppl at blues or jazz clubs. 

Tokyo is full of lonely people. They have an industry catered to them. Maybe you could try what it has to offer?