The question is very board and most responses seem overly specific and only useful by chance (not to dig at anyone trying to be helpful).
Spend more time doing what makes you happy. Learn some things that make you useful to others and learn to identify what both of those things are. It is unlikely that global technical trends, fads and HN users preferences will be the answer to your local problems.
If pushed for something specific that is broad enough to apply to most technical people I would say learn how big picture pieces fit together in your niche. I'm a front-end dev so this means for me to learn networking, dns, packets, tcp, etc. Get a broad understanding of the big picture stuff in your niche. It often pays off.
Spend more time doing what makes you happy. Learn some things that make you useful to others and learn to identify what both of those things are. It is unlikely that global technical trends, fads and HN users preferences will be the answer to your local problems.
If pushed for something specific that is broad enough to apply to most technical people I would say learn how big picture pieces fit together in your niche. I'm a front-end dev so this means for me to learn networking, dns, packets, tcp, etc. Get a broad understanding of the big picture stuff in your niche. It often pays off.