[mpol]

Using brute-force, algorithms or rules is too hard for humans, there is too much going on at the same time. Even Stockfish didn't manage that against AlphaZero :) If you do want to have a more strict repertoire, you could find a few openings that you like and that play naturally for you. The way I choose them is by simply playing them and then see the first ten results. The first 5 games with King's Indian defence were wins for me and felt very natural, the first 5 moves are slow and after that there is a game going. I tried Ben-Oni, but I am too messy of a player and just mess that up, the same with the French. Ofcourse, getting to know an opening better, with the themes that belong to it, will make you better at it long-term.

Anyway, there are so many things going on, you need to feel some intuition or patterns on what is currently important on the board. Rules are so very much based on context, like, for black, c5 is almost always good while f6 is almost always bad. But there are many games with exceptions. And if you play against people of your same level games can just be fun.