I think most of the decent nightlife is around the Shibuya area (Daikanyama, Ebisu, Aoyama, and Shibuya itself).
In Shibuya, itself Rhythm Cafe, Nonbei Yokocho.
And perhaps Fuglen for a quiet cocktail https://tokyocheapo.com/place/fuglen-tokyo/
Although, I have to come clean - it's a while since I set foot in a night club, so I'll leave more details to someone else more qualified. (Perhaps @Lily.Baxter would care to comment?)
We have a post on meeting creative types:
Of course there's the monthly Tokyo Cheapo meet up - you just missed one, but we'll probably have another at the end of Feb.
This group on FB sometimes has interesting events.
Hope that helps!