I'm no expert on it, but this is my advice when you're naming characters. It's what works for me anyway.
1. Remember the whole alphabet exists for a reason.
I'm sure it's very useful that baby naming books split up the names and organise them in alphabetical order. But from a naming characters POV it does create some pitfalls.
When I was naming characters for the Perfect Timing series (a process spread over several months) I ended up with three men named Rupert Montgomery, Rigby Mattews and Rhys Morcant. No idea why, accept I seemed to find a page in the book of names that I liked and I forgot to turn over between visits to the book. Then once I found the initials for the first one, the similar surnames followed.
Rigby Mattews still exists (He's one of the characters I'm editing in For the Duration at the moment). Rupert had to change his surname. Rhys, poor thing didn't get to keep either of his initials.
There are a few more repeating first letters that slipped past my radar in the Perfect Timing series and they are too firmly fixed in my head to rename them now. But, to get around this for future series I try to name all the main characters in a series at the same time and have every name begin with a different letter as far as that's possible.
It's not always easy. If you have a series of 12 stories, that means 24 different main characters names, 48 if you count surnames. Unless we invent a few extra letters, there will have to be a repeat or two, but I find it at least makes me think and be concious of what I'm doing, which is always a good thing.
2. Don't be lazy and tweak successful names.
In Turquoise and Leather, Eric really came to life for me. His character just worked. I smile every time I think about him.
I can't say I particularly liked Eric as a name before I wrote him. Or that I thought Eric was a particularly submissive name either. But the next three submissive male characters I named were called Elijah, Elliot and Eddy. Somewhere inside my head I wanted them to have some of Eric's spark and maybe that was my way of trying to short cut to it.
The biggest problem with this is that Eric's personality would have turned up along with his name. As much as I like him, I don't want carbon copies of him in all mybooks. Elliot managed to establish his own personality, so he survived renaming, the other characters didn't. I keep an eye out for this now.
3. Different names sound like different sorts of characters.
Posh characters tend to have long names. Dominant characters tend to have traditional or old fashioned names. Submissive characters usually get a double helping of vowels. Submissives names are more likely to get shortened. Dominant men are more likely to go by their last name.
One of the characters I wrote about in Whispers is a dominant man (he's also a Vampire, but that's besides the point). His name is Zachariah Radcliff. He stayed as Zachariah through the whole book. It never came up in the story line, but I know if he was talking to other men, they would call him Radcliff. That's just who he is. I just cannot imagine anyone every calling him Zach or Zachy. I sure as hell can't imagine him answering them if they did.
But Rigby and Brennan in the one I'm editing now. They hadn't been talking to each other for five minutes before they started shortening each others names to Rig and Bren in conversation. I'm happy to say the full length and the shorted versions suit them both, so they get to keep their names. That leads me nicely onto point four.
4. Pet names and nic names are best developed naturally.
These tent to turn up for some characters but not for others. I've found it's best not to force nic names or pet names onto characters. Some dominants can get away with calling their lover sweetheart through the whole book, others sound like they can't remember the persons name by the end of the first chapter.
Likewise in some books the dominant becomes refered to as sir or master. Some dominants like that and it works. Some submissives like that too, and it sounds natual when they say it. But it just doesn't work for other characters - it immediatly becomes impresonal and pretencious.
I think it's also a good idea to vary the enderments you use. Not everyone is a sweetheart or a darling. The more personal the name is the more life it will bring to the character.
5. I save up names I really like for longer books.
Not so much advice as an admission. If I really like a name, the sound, the meaning or anything else about it, I don't want to waste it on a short story. I set them aside for full length books.
I also worry that I will somehow use up all the good names far too quickly and be left writing about people whose names I don't like. What can I say, sometimes I'm just weird :)
And since I need to catch up on my editing today, this post is already far to long.
A quick update on my current WIPs...
I have 10,000 words left to do on Time Out. I'm hoping to get most of that done over the weekend, or early next week so I can move on to By the Hour as soon as possible.
I'm also finishing off the second draft of For the Duration today. I'd like to finish that and the third draft this weekend so I can start the fourth draft on Monday.
In the mean time, hope everyone has a good weekend :)