I think older tutorials using classes or deprecated lifecycle methods and things like that can still help you, though it could also confuse the hell out of you if you're not aware of some of the fundamental differences between classes and and using functional components and hooks.

I think for now, it might be better to just stick to newer material, but you'll probably want to learn how to use class-based components too, since a lot of people are still using them. Also, the newer stuff might be easier to grasp with an understanding of how class-based components work.

Codevolution on YouTube has some great videos. He has a new series on hooks that covers all the built-in hooks and also shows how to implement the same functionality with classes. I'd definitely watch the whole thing. The entire series is only a couple hours long, and I think his material is really good for developing a solid understanding of the fundamentals.

Also, here is a fantastic article on useEffect by Dan Abramov.

[A Complete Guide to useEffect](http://

https://overreacted.io/a-complete-guide-to-useeffect/)

One last thing, sometimes going through good older tutorials and trying to update them can be a good way to practice and better understand newer stuff.