When do you use the subjunctive mood?

There are three things that lead us to use the subjunctive mood, instead of the normal indicative.
These are what we call triggers.
1) There must be a change of person in the sentence.2) There must be a relative pronoun being used in the sentence: most often this pronouns is que. 3) There must be two verbs: one 'WEIRDO' verb, and the subjunctive that we form after it.
WEIRDO is an acronym that we can use to remember what type of verbs trigger the subjunctive. It stands for: Wishes; Emotions; Impersonal expressions; Recommendations; Doubt; Ojalá.
Remember these three golden rules and you're on your way to putting the subjunctive in practise !