Some problems with tone are small and can be easily fixed during revision. Others might require a bit more work.
I believe the most important key to remember here is - make sure your very first paragraph establishes the tone you want. This is the first paragraph of my upcoming suspense, Thunder.
Chloe didn’t see Thunder anywhere around. The humidity of the Florida night air soaked her to the bone. She reached for the door, surprised to find it unlocked. Three in the morning – it didn’t seem right. Call it a detective’s sixth sense or experience - someone was watching her. She glanced right, then left, straining to hear anything in the eerie stillness.
What have you learned? It’s three am, humid in Florida. Chloe is looking for Thunder and the door should be locked and isn’t. She doesn’t feel alone in the eerie stillness. The ‘tone’ is set.
Be careful not to change tones for different subjects. For instance, don’t have a detective struggling to deal with killing a teenage perp and then think about shopping for her wedding dress in the next paragraph.
I read an interesting article the other day where novelist Carolyn Chute told Writers Ask: “I write a lot of junk. On and on and on, all this junk. But every now and then this dramatic moment happens, so I lift that out and put that aside. And then I write all this junk: They’re brushing their teeth, they’re sitting there, they’re looking around—you know. Then something will happen and I’ll pull that out. Because those are the only strong things.”
Read your work looking for places where your story says nothing. Such as too much description or maybe dialog that really doesn’t say anything. Boring is bad. When it comes to tone, don’t try to fix the boring parts—toss them. You can’t fix boring.
Two things come to mind when discussing ‘tone.’ One is stick to the subject; don’t start talking about the similarities between three murder cases and end up talking about how you hate the new dress code. Stick to the subject at hand.
Second thing I’d like to mention is don’t hit readers over the head with your point. You can show rescue stations don’t have the equipment they always need to do the job, but resist the urge to drone on how people never step up to the plate – until it’s too late.
Tension and conflict supports tone – No matter what the genre – conflict is as vital to your story as air is to breathing. People disagree, have different opinions, react differently, have opposite interests, have complicated personalities, medical issues or needs, etc. If we all were alike or all thought the same – what a boring world this would be.
Voice conveys tone – Think about a character’s accent or broken English. Think about a lisp or perhaps a stutter. A character’s voice can tell the reader what part of the country he/she is from without spelling it out (you know what I mean). You do this with certain well-known speech patterns; ya’all, eh?, yah, you betcha, etc.
Reveal ‘tone’ through scene descriptions - I showed how we do this with the first paragraph of Thunder. Florida, humid, eerie stillness, three in the morning. Also this paragraph shows the mood of the heroine; fear, tense, and on-guard. Always think about the mood of your character and relay that in gestures, speech, and reactions. These details will enrich your writing and make note, tone comes from being specific and detailed.
Problems with tone – Steer clear of controversial issues, like politics, sexual preference, race, lawsuits, unions, abortion, and the list goes on. Any comment about a controversial subject can be tricky, and you must make sure you don’t ascribe to negativity, you must show motive. Remember you must explain what your characters did and why they did it. Write without being judgmental. You’ll be a better writer for it.