I recently read a book in which the three main male characters' names were Rafael, Richard, and Robert.
Dude, I could not keep those suckers straight.
I fully admit I maybe read a little too quickly at times, and I also admit names are not my strong suit, but … but … c'mon, authors, throw your readers a bone and choose names that won't be easily confused.
Richard and Robert were the worst, because in my mind they're sort of interchangeable "nice" names that are both two syllables and start with Rs and have an R toward the end as well. As I'm skimming along, I can't distinguish them for beans.
At least Rafael is a little bit more unusual and with a different sound, and it was often abbreviated as Rafe (oh, for a Dickie and a Rob, too!), but is it too much to ask that if there are going to be three important male characters that they not have names that all start with the same letter?
Now, I know writers of nonfiction or fictionalized history might have no choice. And maybe there are certain occasions when sequels or prequels inadvertently force similarly named characters to collide. But, for the most part, you as the author are fully in charge of giving your characters names that won't give your readers fits.
To that end, here are my humble suggestions:
1. Don't name everyone with the same initial letter.This is surprisingly tempting. Our brains work in logical trains, after all. When we've come up with one good name that starts with a certain letter, it's only natural to think up similar names first. Keep the wheels turning, and don't settle on your first choice.
Keep in mind letters that are different but sound alike: Corrie and Kerry. I'd suggest avoiding even letters that are the same but sound different: Celia and Chris — because in skimming, it might still be easy to mistake one for the other.
Remember last names, too: Mrs. Adamson and Mrs. Allison and Mr. Arlington would drive anyone to another book.