Aspiring authors often think that using "said" in their dialogue is repetitive. In fact, readers won't even notice it. It's almost an invisible word.
Some authors use "said" exclusively—including after questions, instead of "he/she asked".
If you're worried, then just use "said", or nothing at all.
Examples[]
Not Recommended[]
"How's it going?" Dave inquired.
"Not good at all," cried Hannah.
"Why's that?" asked Dave.
"Forget about it," mumbled Hannah. "It's not your problem."
Recommended[]
"How's it going?" Dave said.
"Not good at all," said Hannah.
"Why's that?" said Dave.
"Forget about it," said Hannah "It's not your problem."