In Chasing Forever Down, I only really use two nicknames, and it's tricky keeping it straight. There's a character who mockingly calls my MC Haley by the name "Sunshine." The nickname itself evolves throughout the story as you, the reader, get to know the character who calls her this. The other nickname that pops up frequently is "Strick." This is another name for Reed, whose last name is Strickland. The thing with nicknames is that not everyone calls someone by a given nickname. There are two characters who call refer to Reed as "Strick", and in my final edits, I had to check for consistency with those two characters. I did find slip ups where one of them said "Reed" instead. How awkward.
It's a very realistic element and used in our every day lives. (I'm officially "Nik" at home. No one ever calls me Nikki around here.) Still, this was something I found to be more challenging in keeping consistent within my novel. Who are some of your favorite characters with nicknames (either from your own works or ones you've read)? How do you maintain a consistency with them?