I'm at the point in First Draft (of the next vampire book) where I have to sit down and organize my Guest Cast, which means finding names for even fairly minor characters so I won't get hung up when I need them. This is always fun, because I'm also figuring out who the villain is, who are the red herrings, what's the name of the villain's wife's maid (or, is the villain actually the WIFE, and in which case how much does her poor spouse know about what's going on?) This is AFTER I've figured out the big technical things like, COULD an ocean liner be attacked by German submarines a day or two from landing in New York? (Yes, after March of 1917).
I have a book called, Mrs. Byrne's Dictionary, (I think I've mentioned this before) which contains all sorts of obsolete and archaic words, like pantarbe (a mythical stone which supposedly attracts gold magnetically) and forslack (to hinder by laziness). A lot of these sound like names. Thus, the maidservant gets called Miss Malkin (a dish-mop) and Don Simon's rather thick-headed henchman is Captain Palfrey (a mild-mannered riding-horse). I have a book of seventeenth-and-eighteenth-century French slang which I can use for the same purpose. There is also, of course, People's Names, by Ingraham - names of every ethnicity and culture including Native American and Tibetan, with sections on ancient Babylon and Classical Greece and Rome. (The Rome section is a doozy!).
Georgette Heyer used to name characters after towns and villages in England, which I've done also. A World Atlas is a fount of possibilities.
Lately I've also used a wonderful website called Fantasy Name Generators, which spews forth TONS of likely-sounding names: Cajun, Ibo, Tahitian, Phoenician... suggested tavern-names and place-names... Some of these I'll use as they appear, others I'll tinker with for something that sounds right.
I start back teaching Feb. 5, so I'm getting as far forward as I can. First Draft is always a bitch.