I've struggled with this too, mostly when transitioning from backend to frontend. So I've tried different approaches.
Most tutors will build a medium sized web app in which you will be able to follow along and then give a go on your own. Working on something that "builds up" will keep you interested on finishing. I have tried Pluralsight and Frontend Masters.
Find areas of opportunity where your teammates could use an extra hand, you can start learning on your own and then jump in. Knowing you'll get to do something productive with it later will keep you motivated.
Recently I've been learning about serverless and JAMstack, Facebook groups are a good place to find gigs, there I stumbled with an opportunity to build a website and it was a perfect chance to try out GatsbyJS beyond the common blog tutorials you see around. It was great for me because not only was I learning and being productive and the same time, I was getting paid to do it!
This is what I did, like 70% of the tools you see there I haven't used before.
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