It is simple. You read many users opinions, you study acoustics concepts and well authorized experience users here are well known.
For example if i need information about speakers, i will consult among others here erik_squires... If i need advices about amplifier i will ask atmasphere. If i need more general information or simply opinions i will among others ask ghdprentice opinion for example .
All the people i know here for years are who they claim they are... I had read their posts...😊
We must be cautious not defiant or suspicious.. Anyway we must trust ourself first for basic information across the web ...And for very specfic information it is easy to have many answers to compare ...
By the way listening with our own ears is a common place fact... How to listen otherwise? No opinions even the most educated and experienced one and even your own ears is not enough at all ... You must learn basic acoustics concepts by training your own hearings in your own room ... That is what i learned and thats was my only advice since i am here ... Some dont like it ... Guess why ?
No one can understand what he hear if he does not have the concept relating to the acoustics aspects and parameters at play... This must be learned the hard way doing it ... Sorry ... Then the best advices and your own ears tastes cannot replace experiments ...