I thought it would be fun to share a little wisdom I've found writing a book with a very large cast and a bit of a tactic I use to implement it.
Threadcaster, as some know, is a quest story - Cat and her horribly afflicted friends travel their small world on a grand adventure. They meet a lot of people on their journey - some important, some not so important, some only important later on. So the questions is - if you meet ten new people every place you go how do you help your readers keep it straight? The answer I've found is as simple as ABC.
That's right; the Alphabet. Reading is a visual activity as much as an aural one and having a lot of characters with similar names can be very confusing. For the eye, starting the name with different letters helps the reader differentiate at first glance - if the character is the only person in the whole book whose name starts with "F" then the reader will instantly say "Oh! It's the "F" name guy!" when he shows up again. Let's apply this to Threadcaster.
As a bit of an exercise I opened a blank document and listed all the letters A-Z in rows, then filled all the names of people we meet with any significance. I do a pretty good job of this already it seems ... but some letters (A, J, and M as it turns out) had an uneven number of characters listed. These might get confusing so I've taken some of the minor characters out and either not named them at all (Is it really important to learn the Mayor's first and last name?) or renamed them (Ashley is a very minor character tucked in with some important ones like Aiden... so I swapped her for Heather since I only had one H.)
I try not to name two characters in the same place with the same letter unless it's plot-appropriate, and I try to make reoccurring side-characters the only ones in their list. This way I think the cast, although large, is a little easier for the brain to sort - and if there's one thing I pride myself on in this book is how easy I want it to read and understand. It's taking a lot of work and brainpower on thsi end of the pen but for you, noble readers, I hope it's pretty easy.