Qualification:
I have never been to such festivals, but recently I wanted to try. Do you have any advice and stuff?
Second question: If anyone knows how to get to niche festivals about anime or anime games, I will be happy if you share your ideas, what I should do to get there, etc
Yup, this. I really recommend going to a small con before you head to a monster like ComicCon or ALA.
Small local ones tend to be where you have time to hang out and meet people. At the big cons, just seeing one person you know makes a huge difference.
Or if you’re really flamboyant and friendly and talkative you’ll meet people wherever.