Okay so, I've mostly got the basics of "general" picking up but here's the deal, I'm mostly into nerdy girls (glasses, timid, not really popular) and I feel like I won't find those at either clubs, bars or concerts like you mentioned. There was a guy who told me to just frequent libraries and while studying Japanese (which makes sense since I'm a Japanese language student) I could try to sit down next to a girl I fancy. Now... I have no idea if that's a good idea or not which is why I'm asking here. See plenty of nerdy dudes in Akihabara with their equally nerdy girlfriends so it has to be possible, right?
Im saying this with love and brotherly good intentions.
You are experiencing paralysis by analysis. For every boost people give you, you offer excuses. You also snicker and judge nanpashi so you subconsciously fear becoming something you deem cringe or awkward.
The "b-b-b-but xy". Nah man.
Listen.
Grab your balls and go for it. Pick a girl and go for it. And keep doing it.
No matter what you want nanpa is a great thing because unlike apps, if you have her attention you have it, its not split.
Also you can much easier get a feel for the vibe you two have. Picture is nothing compared to irl communication.
Tokyo is infinite source of beautiful women of every type. And the only thing between you and them is your excuses. Nothing else. Not much even your Japanese that you are improving daily from what I gather, not your looks, not your height, not your whatever the fuck.
The only thing that is 100% preventing you is you coming up with excuses.
Some venues are easier some less so. I dont really recommend "spam nanpa" where you dont even put effort into it but it can be fun if lots of bros are doing it and you enjoy each others vibes and shit talk. Sometimes it elevates one's mood so you become attractive in that way.
I think opening girls randomly has higher success rate in comparison to nanpa places. But nanpa places have ease of access.
tldr just talk to girls. Give yourself a number of approaches per day and try to hit it, or just total of lets say 1000 and keep pushing.
You are not some special mofo that is immune to getting laid man. Just get out.