It depends on the series. For Mistborn, I build a feel for certain regions and develop names using the linguistic rules of that region. The Central Dominance (and Elendel in this book) had a slightly French feel to the linguistics, and many of the names came from that paradigm.
However, unique to the Mistborn world was the need to give people simple nicknames in a thieving crew sort of way such as Wax, Clubs, Breeze, or Mr. Suit.
For some of my books, I use interesting linguistic quirks that interest me. I’ve taken a number of linguistics classes, and so for instance, for Warbreaker I used just something simple like repeating consonant sounds, so we ended up with Vivenna and Susebron, to give a theme to some of the name.
Some of the names in the book were constructed quite intentionally to fit linguistic paradigms of the setting. Urithiru, for example, is a palindrome–which are holy in the Alethi and Veden tongues. Some names, like Shallan, are intentionally one letter off of a holy word–as to not sound too arrogant. (Shallash would be the holy word; nobility will often change one letter to create a child’s name to evoke the holy term, but not be blasphemous.)
With many, I just go for the right feel. I’ve worked these names over for years and years at this point. Dalinar’s name has been set in place for a good ten years or so, but Kaladin used to be named Merin and Szeth used to be named Jek. (The first changed because I didn’t like it; the second changed because the linguistics of the Shin people changed and I needed a name that better fit.)
Some of your names sound similar to those in other books. Was that intentional?
I ended up with a lot of unconscious similarities in The Way of Kings as I was working on it for such an extended period of time. Cenn wasn’t actually intentional. (At least, I don’t think so; sometimes, it’s hard to remember back to which names pop out intentionally and which do not.) The eyebrows of the Thaylens were, however, an intentional homage, as is the name of the mountains by where Szeth’s people live.
There is going to be some overlap. Sarene is a great example of this; I’m pretty sure that one is just coincidence, though I’d lay odds on Cenn being an unconscious influence.
For Wheel of Time, Robert Jordan actually looked in the phonebook. He wanted to harken to our world, implying the Wheel of Time is perhaps our world in the future or in the past. And so he wanted names that felt like names of people you knew, but changed a little bit. That’s where names like “Thom” came from, spelled with an “H”, or Mat, or so on.
For Wheel of Time naming, I had a list of fans’ names, and I just tweaked those names in order to try and get the same style and feel of naming.