A name says a lot about a person in a single word. The girls names of Ethal, Shaniqua, Jennifer, Lakshmi, and Maria probably conjur very different images in your mind. Names can add diversity to a story or help enforce a time and place.
The worst thing a writer can do is give all their characters the same name. I haven't seen this in any recent novels, but it's very common in the classics. A grandfather, father, and son all named John. This may have been a common occurance back in the day, but it seriously adds to the confusion factor when a reader constinantly has to stop and ask, okay which John is this again?
While coming up with different names for all your characters is uber important, lately a lot of authors have been taking this to the weird zone. We live in crazy times, and just like parents are giving their kids names like Tuesday and Moonshine, authors are expressing thier creativity on the titles they give their characters. I recently read a book with a protagonist named Ever. I was constantly having to stop and figure out context. Every time the word Ever appeared in the text, I had to figure out if it represented a name or an adverb.
It can be confusing to give characters to similar of names (Taylor and Tyler or David and Davis) but it's also a bad idea to give a character a name similar to a common word. I just read a book with a character named Sumner. In and of itself that is not a bad name, except that he was regularly referend to in sentance that read "the summer I spent with Sumner." The word summer was used so often in the story that I found myself stopping to clarify almost as much as I did while reading about Ever.
I've also noticed a trend of authors using the same obsure names. In the last two months, I've read three books with a teenage character named Haven. Granted in the year 2008 there were 481 girls in the United states named Haven, making it the 631st most common girls name, just beating out Irene and Maeve. So while this name is uncommon, it does exist. But in the early ninties when all these teenage characters named Haven were soposidly being born, the name was nowhere near the top 1000 names. But 193 girls were named Isamar in 1992, so why aren't I reading about any of them?
Joke of the Day
Some other names to aviod giving your children or characters:
Denny Juan Heredatt
Frank N. Stein