When I look back on the really helpful blog posts I have read, they have all been really basic. Whether they described a programming technique or a recipe for a new meal, it was a clear description that was important - not how esoteric the knowledge was.
There is a place for complex blog posts on arcane subjects but posts on "common knowledge" are even more important. There is a 15 year old out there somewhere that needs to know how to use the different smart pointers in C++ or how to properly care for a cast iron pan.