My understanding is that the imperfect form (gustaba) indicates that you "used to" do something. "Me gustaba eso" = "I used to like that". The preterite form (gustó) just indicates that something occurred in the past. "Me gustó eso" = "I liked that".
So, gustaba would indicate that something was enjoyable in the past, but it's not anymore. Gustó simply states that something was enjoyable. It doesn't indicate that this is no longer the case.
Gustar normally works in a different way, the object you like is the subject and the person who likes it is the indirect object. You can also use it in different way, using a construction that is closer to the English one, nevertheless is not much used nowadays in everyday speech, only in literature, formal situations and some regional dialects. For example:
- (A mí) Me gustó tu creación.
- (Yo) Gusté de tu creación.
In the second construction the object you like must always be introduced by de, other than that it is more similar to the English "I liked your creation".
As others have said, the subject and object for gustar are reversed from what you'd expect in English. This page goes into quite a bit of detail on it: http://www.studyspanish.com/lessons/gustar.htm
There are actually a number of verbs that work this way. This question comes so often that it would be worth having an entire lesson dedicated to this type of verb.
"gustar" is closest to "to like" in English, but it's generally easier to translate it as "is pleasing to." For example: "me gusta el jugo" = "the juice is pleasing to me" = "I like the juice." Everything else is the same as any other (non-irregular) verb, you just need to know the typical conjugation.