Students often come to me asking about this. This list is not for conjugation (later!) but for deciding when to use the subjunctive. It doesn't really exist in English, so it's hard for Anglophones.
  1. Clauses
    Locate the clauses (the subjunctive part comes after the "que" 95% of the time). There are two clauses (for our purposes). If the first clause expresses any of the WEIRDO characteristics, then the second clause requires subjunctive. This is technically the subordinate clause, but we will call it the "second clause."
  2. W
    Wishes, wants, desires. Yo espero que tú vengas. First clause expresses wish, second clause follows suit with subjunctive form of "venir."
  3. E
    Emotion, exaggeration Estoy triste que amigos no hagan su tarea. In the first clause, "triste" expresses sadness over the second clause - therefore, the subjunctive form of "hacer" is required.
  4. I
    Impersonal expressions Es bueno que ella hable español. First clause is an impersonal expression expressing SUBJECTIVE opinion over the following though, so subjunctive of "hacer" is used. "It is good that..." What is "it" in the example? That's impossible to say!!!
  5. R
    Recommendation, request, requirement Recomiendo que tú no comas. Pido que tú me traigas agua. Necesito que tú me ayudes. The first clauses express each of those traits in regards to the second clauses. Therefore, subj. of "comer, traer, ayudar."
  6. D
    Doubt Dudo que tú puedas tocar la guitarra. No creo que él esté aquí. First clause expresses doubt with respect to the thought in the second clause.
  7. O
    Ojalá ¡Ojalá que mi novia no sepa! I realize it is silly for ojalá have its own letter in the acronym, but this is how it's done. This word more or less means "I hope to god." It actually comes from the ~700 year Muslim occupation of Spain during which the Spanish language became heavily influenced by Arabic. The "alá" there comes from Allah.
  8. Etc...
    There are other uses, I'm aware, but the WEIRDO acronym is a great starting point if you're just beginning to learn the subjunctive or have never quite understood when to use it. Remember, it's all about the uncertain, the emotional, the subjective. If those characteristics are present in the first clause, use subjunctive in the second.