When I was doing some research about the right way to learn React JS, I come across this excellent React Developer RoadMap, which outlines what is mandatory, what is good to know, and what is some extra stuff you can learn as a React developer.
Learn React for free
The ultimate React 101 – the perfect starting point for any React beginner. Learn the basics of modern React by solving 140+ interactive coding challenges and building eight fun projects.
If you are serious about your React skills, I strongly suggest you look at these courses.
Amazing React Projects
Collection of amazing open source React & React native projects
Codecademy React 101: https://www.codecademy.com/courses/react-101
Codecademy Learn Redux: https://www.codecademy.com/courses/learn-redux