I have been looking for some intermediate to advanced guides for fighting games. Youtube is full of beginner stuff. But where to go from there.
It depends on the game you play. After the basics that apply to all fighting games, the intermediate stage is usually learning your chosen game's system mechanics, your chosen character inside and out, then the match ups.
In games like MK and SF the system mechanics are fairly straight forward, but other games like Guilty Gear take much longer to become familiar with. Same goes for characters. In SF, I play Zangief who has bugger all combos, so he didn't take long to learn, but in MK I played SD Cage who took a lot longer. In GG I play Potemkin, who compared to other GG characters is fairly simple, but compared to other games is really in depth.
So once you know your character's combos, you need to figure out the match ups, and get really deep looking at every situation. What can that opponent do? When is it your turn, when do you have to keep blocking? How do you capitalise on your turns? Are the character specific mix ups? Are there mix ups you should avoid altogether?
There will be videos about this on YouTube, but once you're past the beginner stuff then video learning becomes less useful than actual training mode time, studying match ups and improving your reactions with training drills. Even if a video existed that broke down every situation you'd ever encounter and what to do to counter it, watching said video wouldn't be enough. You'd still need to set up the dummy in training mode and practice until it became second nature.