As a web developer, you will have to become familiar with documentation. I think that documentation is an underrated and overlooked way of learning.
Next think you want to learn, go directly to its documentation. Forget about videos or tutorials. Just go into the documentation, open their link to their Codepen/JSFiddle if any, and start playing around. Bonus learning points if you apply it in a slightly different way to a personal project.
I did it today with React Transition Group.