Sorry to interrupt a very interesting thread--I swear I read a post here once about handling dialogue when we don't know the names of the speakers. As in someone listening in on a conversation, say, between two women and a man. Like the first time one speaks you could say, "the man with the ill-fitting suit" but when that person speaks again, how would you identify him in a non-cumbersome way? That kind of a thing.
But I can't find the post. If it rings a bell would you mind directing me?
Jenny, I couldn't find such a post. Maybe we did write it and our Super Deluxe Sidebar Labeling System (tm) has failed again. Someday, I swear, I am going to sort out our labels. (Stop laughing.)
So, let's start by setting some parameters. You're writing a secondary character important enough to speak but not important enough to identify by name. (Or perhaps there is some other reason for hiding the name.) That secondary character doesn't fall into a neat character type, so you can't just write, the waiter said, after his lines.
Here's a handy two-step process for making this easy.
Pick an active identifier that gives you room to play.
You offer an ill-fitting suit. This is a good choice, much better than a static cue or a common trait. Here's why--
Use beats to draw the reader's attention back to that active identifier.
Let's use your example of the man in the ill-fitting suit. The first time he speaks, you can identify him as just that, the man in the ill-fitting suit.
Now let's brainstorm some actions taken by a man who wears that ill-fitting suit. Does he tug the cuffs? Play with the tight buttons? Hike his pants up repeatedly? Shrug his shoulders when things feel tight?
Use these things as beats in that character's dialogue. It will cue "ill-fitting suit" without being repetitive.
"I never saw that woman before she turned up in the diner." The man tugged his frayed cuffs down. "She sat by herself and didn't talk to anyone."
Detective Jones made a note on his pad. "So why did you remember her? You identified her body in the alley."
He popped open a too-tight button. "Kinda hard not to notice a soaking wet, barefoot woman who comes into a diner and orders pie. And pays all in dimes. You remember a thing like that."
You see? If you had tagged the nameless character with something more ordinary or static -- "the tall blond," for example -- you wouldn't have all these options for beats. Well, maybe you could have him run his hands through his blond curls. That's a common move, so common the reader might yawn through it. Plus, there might be many blond men in your book. So this might not be unique enough to help the reader keep things straight.
Maybe you could have him bend to get through the doorway, but how many doorways will he walk through in the course of the conversation? You need an identifier that gives you options, that's vivid, and that is unique enough to relate back to only one character.