Junji Zhi has a newish (since September) blog that he calls Emacs TIL. As the name suggests, it’s a collection of small tips that Zhi learned on any particular day. The tips are all short—one or two minute reads—and easy to digest.
Many of his discoveries will be familiar to experienced Emacs users but, to me at least, some were new. It doesn’t really matter because they’re so short that you don’t have to spend much time with them. If you’re interested in the opportunity to discover short Emacs tips, it’s worthwhile subscribing to his feed. It’s not a high volume blog so you won’t be overwhelmed.