So discernment is the ability to see what those forces are clearly and to identify, weigh, and judge. And finally, choose the path most aligned with God's desires for you and the world.
Therefore, it is more complex than mindlessly following specific rules. One must also trust one's impulses and God's actions within one's heart.
How does one discern?
Try to be "indifferent" and be free from everything that holds you back from following God's desires. For example, if you are discerning whether or not you will visit a sick friend in the hospital and are worried about whether you will get sick, you are not "free." Something is preventing you from doing good. Indifferent" does not mean you don't care, but you are free to follow God's wishes.
Ask for God's help; discernment does not happen on its own. You need God's help to choose the right path and use the Gospel and the teachings of the Church as a solid starting point. Do this in the context of prayer. "trust your heart, but use your head."
Weigh the different "movements" within yourself to see which originate from God and which do not. For example, St. Ignatius says the "good spirit" will bring support, encouragement, and peace of mind. The opposite is the 'Bad Spirit.' This one, causing anxiety and presenting false obstacles to hinder our spiritual progress, the 'evil spirit' will say to us, "If you forgive, people will see you as a carpet!"
You can turn to other practices Ignatius suggests if there is no clear answer. You can imagine someone in the same situation as you and think about what advice you would give them: this can help lessen the influence of our disordered desires on discernment.
Finally, after making a good discernment, you will experience a feeling of what St. Ignatius calls "confirmation," or a sense of rightness. You feel in tune with God's desires because you are on the same frequency as God. And this naturally brings peace.
