No underlying meaning or structure Letters of the alphabet, the names of people, and the arbitrary key sequences - rote learning, the bane of modern existence.
Some things do require Rote learning: the letters of the alphabet, for example, but even here we add structure to the otherwise meaningless list of words, turning the alphabet into a song.
Learning arbitrary things is difficult - takes considerable time and effort - May be you can Start with why - or using Meaningful artificial structures