It's incredible how little attention is paid to data modeling and querying in the education of people entering the software engineering workforce. Getting your database model right, on the logical and physical level, will make developing and deploying any data-driven app simpler and easier. Getting it wrong? No modern programming language or architectural pattern will save you from the worst kinds of bugs, workaround…
This reminds me of the famous Rob Pike quote:
"Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming."
I've often found that if I'm coding something and the code starts looking increasingly gnarly, that rethinking the data structures / data model will clean up the code.