Micro learning

Hi folks how are things,

I'm going to try and "Mirco learn". What It is is reading and learning about stuff in passive instead of looking at Facebook, twitter etc. (for those who aren't sure)

Mate of mine is an electrician and does this on the daily and I've seen his knowledge go through the roof.

Question is what and where do I start. Do I pay for medium? Do I read docs (some are a hard read) help appreciated. Cheers

For reference. I'm a backend java dev in Fintech