Mnemonic+Device+or+Original+Analogy

First of all, I always remembered the difference between a metaphor and a simile (similes are comparisons using 'like' or 'as') because simile starts with S and 'as' has an S. Might seem silly and unlikely to be helpful, but it worked for me every time. Consider an acrostic, a rhyme, a song, a funny list of similes about 9th grade, etc.