After hundreds of hours spent on answering questions on Stackoverflow, I observed a few barriers of entry that ES newbies struggle with. It's first and foremost the formidable query language.
Now, most of us learn a new technology by reverse-engineering what works elsewhere. So I've published a handbook with carefully curated, practical examples that demystify the query language and offer a solid foundation to build on — https://elasticsearchbook.com
Hope it helps!
P.S. I'm new to the forum and hope this is the right group to post this into?