An attempt at something possibly comprehensible
OK, I'll try to take it down to something possibly comprehensible.
There are universal rules in polyamory, but they can never be formulated by any outer authority. These rules describe the grammar of the language of love, and in their native form they can only be sensed through the deep heart, beyond the flow of emotions.
In that way, it is basically completely universal, yet at the same time completely individual. Because it emerges in each individual, in a sense an integral part of the individuation process, and therefore unique.
Why polyamory? Because that is the general, default situation. Mono is a special case where much focussing is applied, but this leads to the danger of losing the contact with the bigger picture. On the other hand, lack of focus or too much obsession with the bigger picture may lead to losing the contact with the concrete, physical and psychical aspects of oneself, thereby severing the bridges to others, and making the individual journey more complicated.
What can be said about them? It is probably not possible to make any kind of comprehensive or definitive list, because they operate on a deeper level and are interconnected. But open communication, empathy, mutual respect, love, caring, self confidence, honesty, ethical symmetry, commitment, deep interest and an urge for common growth are aspects that must be active in order to balance the repercussions of the physical and biological processes associated with the practices. It is not about a given way, it is about finding and creating one, and stand up to the challenges life can provide us with.
Whenever we find our interactions are lacking in open communication, empathy, mutual respect or the other aspects, we should take that as a reminder and if at all possible, act on it. It is much easier to use the foundation to see that something is wanting, than to produce ideas for improvement, and it has to be that way. Because we always have to apply phantasy to ethical challenges, they can never be adequately tackled by following some given procedure, we must mobilze creativity.