How to Teach Gustar
Most textbooks try to condition students into using gustar properly in the rather sneaky way of introducing it in a preliminary lesson, using sample dialogues with ¿Te gusta...? and Sí, me gusta... or No, no me gusta... to at least plant the idea. It's a good idea. It works -- until they are confronted with the actual lesson about gustar and verbs that also require the use of the indirect object pronoun to show the person impacted by an action (known classically as the dative of interest).
Here is how to teach gustar and friends: Don't start with gustar! Why show them this verb first when you can condition them to the use of the indirect object pronoun using other Spanish verbs whose English counterparts also require the indirect object pronoun?!
The lesson about gustar usually follows the introduction of indirect object pronouns. Sometimes gustar and other verbs like it are the vehicles whereby the lesson on indirect objects are taught. In either case, start with fascinar or encantar. The whole class can have fun with these because you can make them talk about movie stars, famous people etc., in playful ways.
Before doing anything in Spanish, remind them of how English uses indirect objects for showing the person who is fascinated or enchanted, the subject being the one who does or causes the enchanting or fascinating, e.g., She fascinates me; I enchant her, etc. Review the Q&A format with them by modeling it, thus: Q -- ¿Te... ; A -- Sí/no me ... It is important when you show them this format that they see that the only real structural difference between Spanish and English in this situation is that the pronoun comes before the conjugated verb (deal with complementary infinitives in this context some other day).
After doing many questions and answers, either as a class or in small groups (students can be asked to find out about each other's favorite or least favorite celebrity), then they will be conditioned to seeing the Object-Verb-Subject or Subject-Object-Verb sentence structure.
Don't lose that momentum. Write the verb disgust on the board and ask them to each write down one example of how it is used it in an English sentence. Have a few of them read their answers and point out that it uses the indirect object pronoun, e.g., Anchovies disgust us (I rather fancy them myself...).
Next, without delay, draw a line through the dis- prefix, thus: disgust. Tell them that since the dis- prefix makes the root negative, what would gust mean if it really were an English verb? This is a critical moment, because many of them will say "It means you like it." Don't panic! Tell them to use gust as if it were a real verb. In order to do so, they will have to use the indirect object properly. Now you have them where you want them! The next step is to point out that gustar works just like the hypothetical English verb gust.
The other often problematic verb in this category is doler (ue) which is better understood as to cause pain to or to be painful to, just as gustar is best translated as to please.
When I find students still having difficulty with gustar, I write two sentences on the board, English on top, Spanish beneath: I like pizza and Me gusta la pizza (or La pizza me gusta), then I tell them two things. First, that logically, one eats pizza -- and the liking is a result of what pizza does to your tastebuds. Secondly, I show them how subject becomes object between English and Spanish.... if they understand the pizza as a subject in that sense, then they sometimes can appreciate the fact that the subject of the English sentence is the object in the Spanish sentence, where the pizza is acting on the person.