One thing new writers often worry about (one of many many thing) is “people will surely be bored out of their skulls by all the times I use ‘said’.” But generally that’s not the case. Readers hardly notice it. They mostly notice when the writer is straining to use any word other than ‘said’.
Plain, unvarnished “said” is commonly accepted as the best speech tag these days. Lists do float around the internet of “alternatives to said”. They often pop up on the NaNoWriMo boards during the event, at which point more experienced writers start waving their arms and shouting “Noooo!!”
One reason not to use them is that they are a form of telling not showing. They either repeat what the dialogue just told us, or they tell us what to think about the dialog. Don’t say “he whined”, have him say something that makes us think “he’s whining.”
Another is that they distract from what’s most important—the dialogue himself. If we’re busy wondering exactly why the writer used “expostulated” we’ve forgotten what the character actually said.
And don’t fall into the trap of using said but always adding a description of how it was said. Which can become absurd.
“I got all six numbers on the lottery,” he said winningly.
“The chicken is still in the freezer,” she said coldly.
Some older books might be different, but unless you plan to go back in time and sell your book in the nineteenth century, that’s not relevant. Some modern books might also be different, but they’ll be distinctive style choices by the writer. They’ll be the exception that proves the rule.
However like so many “rules” it turns into an absolute when it should not be. Shouted, yelled, whispered etc is fine here and there “Oh my god, here come the dragons! We’re all going to die!” calls for more than a mere “said”.
There has to be a balance
Often the best alternative is nothing. If it’s clear who is speaking with no tag of any kind, then leave it off. Another option is an “action tag”.
“Surely there’s something we can do about him.” He glanced at the gun cabinet.
So far so good. But some people take to heart the advice to do away with as many said tags as possible and make them all action tags instead. Usually of quite pointless clichéd actions. By the end of a passage of that I want to scream at the characters to stop bloody fidgeting and just sit still and talk.
Action tags are great, but should be meaningful, not mere fidgeting.
The key is definitely balance. Mix it up, always. Use said most of the time and sometimes a simple descriptive alternative (shouted, whispered etc), or use no tag, or an action tag. Very rarely a “fancier” word for said. Very rarely.