It is especially useful to combine the keyword method with other strategies. For example, a young child might first learn the meaning of interscholastic by picturing himself entering another school through the entrance in order to play an interscholastic sport. It would be more likely that he would remember this word if he contrasted it with intramural sports, which are played right at the home school. (The ra distinguished intra from inter.) If the child never participated in or attended either interscholastic or intramural activities, the level of encoding (and memory) for these words would remain superficial (and temporary). However, if the child participated in both activities and continued to notice the difference between the prefixes, learning would become more permanent. In addition, if the child learned that words have prefixes and that prefixes have meanings, it would become even easier for long-term learning to occur. If he looked at words like international (between nations) and intervene (to come between), he would have a head start on a huge number of words that use that prefix.
(While the preceding paragraph describes an excellent way to learn the meaning of words, it has limitations. Oddly enough, if we pronounce the word inter differently and apply it to a dead body, it has nothing to do withbetween anymore. When we inter a body after a funeral, we place it in the earth - from the Latin in terra. Note, however, that for mature learners, the very activity of noting that this is an interesting exception to the original association makes it easier to remember the meaning of the word and to use it correctly.)
In short, the keyword method helps learners acquire an initial, surface familiarity with a word that can serve as a first step to enable them to recognize the word when they encounter it later. Further active processing can make the word a permanent, automatic part of the learner's repertoire.