Finding the right name for your character can be elusive and sometimes it seems you'll never find the one that fits best. Here are some tricks to try:
If you're absolutely stuck and can't unearth your character's name, the chances are you don't know your character well enough for him/her to reveal his/her name to you. Find out more about him/her, and then try again.
Another useful trick is to acquaint yourself with your character's parents. Why? Because it is the parents who usually name their children. If you know the parents, who they are, their personal values and habits, their conceits and preenings, their failings and fears, who they admire and who they abhor, their hopes...you will know what they're likely to name their kids.
Sometimes names just appear when you need them and you simply need to be awake to the possibility. Serendipity opens doors when you're searching. I recently found a name written on the sand on a beach in P.E.I. for a character whose name had eluded me. I tried it out, tentatively at first, and to my delight, it fit.
Here's another way of finding your characters' names: soak your subconsious with the thought of locating that name before you go to sleep. Maybe you'll dream up a name that is right. Maybe you'll wake just knowing it.
If you're not certain of your character's name, or even if you are, be sure to say the name out loud. Is it a name that fits your character? Sounds like your character? Is it easy to say or difficult to utter, awkward to roll off the tongue? The musicality of it needs to be pleasing to your ear -- or perhaps not pleasing if that is what you're aiming for.
Saying all your characters' names out loud will help you to spot inadvertent mistakes such as all of them sounding alike, or starting with the same letter, or ending with the same sound, or having the same number of syllables. Subsidiary characters names can be changed more easily, I find. Although at times I've found those difficult to change as well, if the character is adamant about it.
Saying your characters' names out loud is a great way, too, of finding a nickname. Nicknames often arise because the character, when a baby, couldn't pronounce her/his own name. That's how I came up with Nobby, for my character Zenobia in A Friend Like Zilla. Saying Zenobia out loud, and trying to figure out how baby might say it, helped me come up with Nobby, which fit my character just right. So right that she thinks of herself as Nobby and hates Zenobia. She is a Nobby, but not a Zenobia!
Another way to find nicknames is to unearth the traits and oddities your character displayed as a baby or a toddler. A nickname such as Speedy, for instance, might arise if a baby is particularly fast at crawling. Red, in my novel That Boy Red, got his nickname when he was a baby because his hair was red back then, although it no longer is. I'm not entirely sure how I came up with Gooley for Red's friend in That Boy Red -- it just came and it seemed right. But since his name is Graham, I suspect that he came by it because either he, or a sibling in his family, distorted Graham.
A last reflection: your characters do, of course, represent some aspects of you and your tastes. I like my characters' names to be spiced, to be unusual. Perhaps it's because my name is not the easiest to pronounce or to remember. It's an unusual name. It was an unusual name even in India, where I lived as a kid; I was plagued with mispronunciations even though at times I relished not having a common name.
Apparently it was an aunt who came up with my name -- I wonder if she had the sight? Rachna means creation, or literature.