Creating characters is either a challenge or a breeze, depending on what kind of a writer you are. The basics are often quite simple and the pattern is, of course, followed in all types of entertainment. Hero, Villain, Heroine, Villainess, Supporting Cast ... etc.
The one thing that I recommend in character creation is to list the letters of the alphabet and then fill in those letters with the first names and last names of the characters. That allows for variations in lettering because I, personally, don't like to have a lot of the same letters for my characters. That's not to say it won't always happen, because some names automatically attach themselves to the idea of a character and it's hard to change it once they've been created in the mind.
I ran into this issue with one of the major characters in The Double Club. He started out with a plain name and then I changed it to something more interesting to me. It wasn't easy to adjust at first, because for at least 3 books, he was named one thing and then I changed it to something else. For a while, in my mind, the plain name became his middle name to adjust to the change.
It's like being friends with someone for a while and then all of a sudden they change their first name. John becomes Mortimer. Something like that. Took some adjusting, but by the end of the Series (to date) I had adjusted to the change and it became his new identity entirely and the old name was long gone.
But back to what I was saying about the alphabet ... It looks like this.
Albert, Anderson
B
Connie
Daniel, Danvers
Edwards, Elias
F
Gerard
Fill in the letters with first and last names. I do that because I often refer to some male characters by their last names, especially Villains. Doing this kind of naming allows for some variety. That way, you don't have a lot of characters with the same letter. I feel that it's important to have variety because having a lot of the same letter names doesn't work for me.
Daniel went to the river, seeing David racing to escape the clutches of the evil Gerard as he and Garrett clutched the stolen money tightly .... Just to give a brief example.
The only time that I tended to have same letters for names was in my book, LACONIA, where the names of the Greek characters followed the naming of their parents. I named the children after their mothers, regardless of the child's gender. Tiro was Thyia's son. Otonia was Orthia's daughter. Kleitos was the son of Khloris. Normal naming conventions don't always work like that in certain cultures, but remember that this is your work of fiction and you can do what you like in your world.
It's part of the creative process to take a few liberties to make your characters come alive in the manner that you're comfortable with. I wanted the main characters named after their mothers, not the fathers. Not all were like that, however. Skiron is Tiro's brother, and they are the sons of Stratios. Still, though, using the letter S. Otonia's brother is Odius, and he's the son of Orthia and Mantios. Lots of O's in that family.
That said, remember that you have to stick with the types of names that were found back in those days (for example) if you're writing Ancient Greek fiction. You won't find a Charles Anderson III or a Stephanie Miller running around in Sparta that's for sure. :)
Naming can be a lot of work and it is also a lot of fun, because once you have a solid name that you're good to go with, the character will begin to come alive and that is exactly when you know you've got it right.
I get a lot of my ideas from baby name websites. They have all kinds. There are ethnic names like Italian, Greek, Scandinavian, depending on your plot or types of characters. There are simple names, exotic names, etc.
Look around. See what works for you. It's also fun putting the type of name with the type of character. I like 1 syllable names for masculine male characters and pretty or exotic names for my females. I like sinister names for my villains. Whatever works for you, do it. Create and explore.
Whatever you choose, it will work and if it doesn't, there are PLENTY of names to go around if you don't like the names you initially picked out. If it doesn't feel right, see what else you might like.
Names are important. People will associate your work with them. A good example is my character Morgan Callahan from Blackridge. I've had people talk to me about those books and they always remember Morgan. Always. There are a lot of characters in the Blackridge Saga, but everyone knows who Morgan is when they talk to me about the books.
That's how you know you've made an impact on people, when they name your characters when they talk to you about it. Something like, "Oh, what's-her-face from Blackridge? I love her!"
Yeah ...
Pick your names carefully. They are everything.