What shall you name the character? After all, it's a whole slew of baggage.
First of all, the name needs to distinguish the character from the others. This is even more important in a tale than it is in real life. You do not want to confuse your readers with which character is what. (The cast of thousands is particularly bad, of course.)
In particular, you don't want to confuse your dyslexic readers. If you can give all your characters names that start with different letters, that is wise. If not, you want them to have different opening letters and different shapes. "Martin" and "Margot" are not so wise as "Max" and "Marguerite."
This also helps in that you don't want your spelling checker to suggest one for the other. You certainly don't want it to miss that you mistyped a name as the other. And if you have autocorrupt on, it may do it for you.
Past that, your character's name should hint at his personality, social position, and world-building while fitting in harmoniously enough with the other names to make it seem like they came from the same world without tipping your hand by making it obvious.
This is all the more important for a bit character, or even a piece of the back story who will never appear onstage, because they have so little else to counterbalance them. They're that important for major characters only on introduction. (I once read an article on naming soap-opera characters that commented that if you're introducing the mayor, you can't name him Lefty, but if you have a character named Lefty, he can run for mayor, and win. First impressions are so important.)
Still, unless you can change the character's name within the story -- which is seldom because it needs to both make sense and not confuse the readers -- the major characters must bear the name for the entire story. I once had to ponder giving a girl a name that a doting mother would bestow on a girl she wants to think of herself as especially special, but which, either in itself or as a nickname, she can bear the rest of the story.
Doing this, I almost always have to find a name. (Inventing them is another route, but I never was any good at it.)
I once read a writer warning against naming a character too early. The argument was that names have baggage and you will tag your character with that baggage without realizing it.
That is, in fact, exactly what I am looking for in a name. I try them on, and if they fit, the character type summed up in the name is obviously the character I am looking for. An economical way to define them.
That is a writing aid, not a writing technique. Esmeralda does not conjure up the same image as Jill, but if your mental image of Jill has blond hair, you must give her it, and if Esmeralda loves to garden in her greenhouse, give her the greenhouse and put her into it.
Then, in my high fantasy milieu, I want to ensure it indicates the right sort of time and place that is at least suggesting analogous situations. If Carolina is not found earlier than Georgian England, or Stella than Renaissance Europe, I don't want them in a Dark-Ages like milieu. And I certainly do not want to set a story in pre-conversion Scandinavia with a heroine called Kristen.
Though, of course, impressions are more important than accuracy. Tiffany is a good solid medieval name -- even spelled that way, sometimes. It was popular for girls born on the feast of -- Epiphany! (What a surprise.) But that's not what people will think.
If you do start with the name, and it's early enough in the idea development process, it is, of course, certainly possible to consider whether it's a suitable milieu. If you think the heroine may be named Caroline, would the story work in the first dawning of the Industrial Revolution? With such an era, it can be a lot easier to add names, by looking for sources about that era's names.
That is because all the names should fit together. Some can be anomalous, but to underscore an anomalous character. That the wizard is Theodorius among the Tom, Molly, Jane, Jack, Harry, and Tilda shows that he's unusual.
Baby name books may help with suggesting names, and even possibly giving the correct source cultures. They are unreliable for eras, you may have to research that.
They also have those dangerous things, meanings (sometimes even correct). You may name a character Thomas, but don't expect anyone to know from that he's a twin.
Some names, of course, wear their meaning on their sleeves. Rose, Angelo, Honor, Maximus, Scarlett, Leo. . . and if they happen to be typical and plausible names for the era you are creating, you still have to have characters make lame jokes about a lion-tamer named Leo, but once you do that, you can run with it. (If the name is somewhat obscure, you can have a character whoop it up, and then explain what in the world is so funny about a sculptor named Peter.)
You can sometimes get away with a theme among names. A family with Daisy, Rose, Lily, and Iris, or Honor, Patience, Verity, and Prudence, strongly characterizes the parents. On the other hand, it does burden the story with names that draw attention to themselves.
There is an art to juggle the names so they draw attention to the character, and the right sort of attention. There's no substitute for practice there.
The names are almost the most important thing for a character, because they have to drag that around with them for a hundred and twenty thousand words or more…with no escape.
Another point, they should be culturally consistent with each other, which then raises the bugaboo of the culture itself. Nothing turns me off more than bad naming culture and conventions. I will DNF so fast…
Additional thought on names (especially for characters in fictional societies).
How long should the name be? A name with twenty or more letters in it would be hard to spell every time it is used and how often would a name that long be used in that society?
Oh, as Pam Uphoff found out, it's one thing to use those long names in one book but another to use those long names in future book. 😉