[ANH]

I started here: http://reactfordesigners.com/labs/reactjs-introduction-for-p... (h/t tptacek).

And then I found the egghead.io videos particularly helpful. Nice bite-sized chunks, very focused: https://egghead.io/technologies/react

There are a number of free lessons. I found them useful enough to pay for a subscription. YMMV.