I started thinking about memorable names in the context of genre fiction, as I was reading the book¬†The Goblin Emperor¬†by Katherine Addison. ¬†I absolutely loved the book, but what hampered my enjoyment at times was the incomprehensible naming of people, places, and things in the fictional universe of the story. ¬†For example, the titular Emperor has two sets of servants: the nohecharei, who are like bodyguards, and the edocharei, who are his attendants. ¬†There is one character named Tethimar, and another named Telimezh. ¬†It was challenging for me, an avid reader of fantasy, to keep everything straight.
It's clear that the author of¬†The Goblin Emperor¬†decided to value authenticity within the fictional vernacular she created over the reader's ease of understanding, and it is not my place to condemn that choice. ¬†However, it did get me thinking about what features of fictional names make them more memorable, especially within my discipline of game design, where the narrative has less room for rote repetition. ¬†Below are a few ways of keeping your proper nouns lucid.
1. Decide whether it ought to be a proper noun at all.¬†¬†Sometimes the best name is just a description of what the place or thing is. ¬†Take a look at this fragment of a map from Metroid Prime to see what I mean. ¬†Of 10 named places, only 2 include¬†proper names. ¬†The rest are simply descriptive.
2. Use a close variant of an existing name.¬†¬†It may feel a bit like cheating, but re-using the existing circuitry in your player's mind can be very effective, and serve the overall enjoyment of the game. ¬†Writers do this all the time with place names like "New Tokyo" or "Earth II." ¬†Slight variations work for human (or other sentient being) names as well, such as¬†Snow Crash's "Da5id."
Needless to say, to pull this off, you'll have to have some idea of what your reader considers a 'common name,' so this will be culture-specific and may need to be localized.
3. Accompanying titles.¬†¬†People tend to remember the relationships between people and places better than they remember the names. ¬†Think back to the last time someone described the plot of a half-remembered movie. ¬†It probably sounded something like "...and then the main guy's best friend went back to their old apartment and got the thing..." No proper names at all, just relationships. ¬†We can use this to our advantage by putting the relationship right into the name!
The simplest example is titles¬†like "Professor," "Captain," "Archduke," "Counselor," etc. ¬†If you're in a more fantastical setting, you can use things like "King-son" and "Friend Luke" as names, too. ¬†Anything you can do to associate the name with a relationship will help, and when you've repeated it enough times you can drop the relationship prefix without confusion.
4. Distinct explicit or implied ethnicity¬†can make each of your names distinct. ¬†If you have three main¬†characters -- one an American farm-boy named John, one a burly Norwegian named J√łhan, and one a Chinese national¬†named Jao Han, the player will remember the names distinctly, despite how similarly they are spelled.
5.¬†The Bouba/Kiki Effect¬†is an apparently universal human trait which makes us associate certain qualities of sound with physical characteristics almost¬†synaesthetically. ¬†Hard angular things are associated with hard angular sounds, like "knicknack" and "porcupine," whereas softer, rounder things get softer, rounder sounds, like "balloon" and "butterfly." ¬†You can use this property of natural language, making your names tacitly descriptive of their subject. ¬†If your villain is sharp-nosed and bony, you may want to name him "Jack" instead of "Bob." ¬†Likewise, a domed hall might better be "Woterbund" than "Rinkertin."
6. Gendered Suffixes¬†cause many names to be¬†self-descriptive,¬†at least to english-speaking ears. ¬†For characters that identify as a certain gender, certain sounds can serve as clues. ¬†In vowels, for example, -a, -i, and -y sound more feminine than -o and -u. ¬†For example consider¬†"Brandi" vs "Brando." ¬†There are exceptions, of course, but I think these indicators still have their place in some¬†fictional worlds.
7. Uncommon letters¬†in proper names should be hoarded like the precious resource they are. ¬†Don't use them all up in a single name like "Quizikjax." ¬†Doling out one uncommon letter to each character can make each¬†name stand out, but not overshadow any others. ¬†The least frequently-used letters in english are Z, Q, X, J, K, and V. ¬†However,¬†Even the most-used letter, "E," can seem weird within a name¬†where it's not expected, like "Melodee," so context can make a big difference.
I hope these ideas are at least thought-provoking, and are of use as you create and name people, places and things in games and elsewhere.