I suggest you really practice the fundamentals, especially es6. You're gonna use a lot of es6 concepts in React. Really learn the fundamentals and you'll be fine.

Most importantly, practice everyday. Take 10 - 30 mins to create a small react app. Spaced repetition is a very powerful concept in mastering any skill. Finally, try building a small project with React. Anything you like. Just build something, here's why:

1. You'll learn more by building a small project yourself than watching those videos/tutorial of any kind, because you'll get to a point where you'll have issues with your code, things won't work, (trust me, this happens alot to beginners), then you'll research online. This'll give more understanding about how React works, than just watching tutorial.

2. You'll have a small project in your portfolio, which can be useful later on.

Good luck.