Writing good dialogue by keeping it concise means that you don't just cut the novel's speeches to the bone - you cut them to the very marrow.
Here is an example of what I mean...
"Hi, John. How are you?"
"I'm fine, thanks, Mary. And yourself?"
"Oh, I can't complain," she said. "Actually, I'm glad I bumped into you. Are you coming to the party tonight?"
"I hope to, Mary. It really depends if I can get off work early."
"Have you asked your boss?"
"Not yet," John admitted. "McNulty's having a bad day, to tell you the truth. His ex-wife called. She wants money again. I'm waiting to pick the right moment."
"Is there ever a good moment with that man?"
"Sure," John said. "Catching him somewhere between his third and fourth scotch usually works."
"Hi, John. Coming to the party tonight?"
"If I can get off work."
"Have you asked?"
"The boss is having a bad day," he said. "Ex-wife troubles. I'll pick my moment."
"Is there ever a good moment with McNulty?"
"Sure. Somewhere between his third and fourth scotch."
Don't strip these things out completely, because you still want conversations to sound natural.
But fictional conversations, if they are not to bore, must cut to the chase a lot faster than real-life conversations.
Because very few people do, and it is no different when writing dialogue for characters in novels.
Writing colloquially not only speeds up the dialogue, it also makes it sound more natural.
And if three words will do, so much the better. Of course, you need to make allowances here for the character speaking.
Some people are simply more verbose than others!
"Dialogue is like a rose bush - it often improves after pruning. I recommend you rewrite your dialogue until it is as brief as you can get it. This will mean making it quite unrealistically to the point. That is fine. Your readers don't want realistic speech, they want talk which spins the story along."
- Nigel Watts
Speaking more generally, though, the best way to achieve this concision when writing dialogue is to trust your ear.
You simply need to revise passages of dialogue again and again, trimming and changing them each time. And when you don't think you can revise the dialogue any more, go through it one last time and cut out something else.
The art of writing good dialogue demands it.
Next Step: I have already looked at two ways of writing good dialogue in fiction...
The final secret to writing dialogue which keeps readers turning the pages is Making the Dialogue Flow...