I first went to a water garden store for my first bits of information. They suggested to read a book on pond construction , which they sold. It was a good book, not great but had one saying in it that stuck, plan it out build it bigger...................................
We attended a local water garden fair at a local water garden park which was know for its water lilies and lotus. We were invited by the Austin Koi Club, information we got from them was way different than from anywhere else. I believe they were more interested in a better environment for the Koi we wanted as opposed to what the pond looked like.
I was told good information was available on the internet, so I used and still do use this resource.
Like anything in life, on the internet or in a book, gleaning what is truth and fiction is solely in the hands of the person seeking the information.
When in doubt, I have many resource's I can call on (on the phone) . I do not believe they would lead me astray as they are trusted mentors who have been in the hobby (business) for many years. I learn what I can then ask, whom I know to firm it up..............................................