Death is Meaningful to Those That Live:
I'll admit, I'm a cold-hearted killer - of characters. Parents, friends, siblings, lovers - they're all on the chopping block, with the sword of Damocles hovering over them.
Death can have LOTS of uses and significance. But the reader is more likely to be angry at you if you kill a beloved character. So you need to pick and choose when you give them the axe.
The beginning of a story is a great place to kill a significant character. You want lots of emotional value up-front to get a reader drawn in. The challenge is to get them to care enough for a character, without feeling cheated when they die. The key is to make the death significant to the protagonist.
Deaths in stories matter most to the characters in the story. Kill people based on what is significant to them. The MC's uncle is murdered, causing her to become a terrorist. Her father is disappeared by the secret police, justifying violence against the state.
- You can switch the meaning of a story by having such deaths changed in meaning. So if the uncle's murderer ended up being mentally ill (but the MC didn't know), it makes revenge for the uncle's death a symbol of why we should give forgiveness over taking vengeance.
Minor characters can certainly be killed if their deaths advance the plot and have meaning. A brother gives up his life as a sacrifice in place of his sister. This can also serve to reinforce messages that are central to the story. But writing is critical to making the point you want. So dying heroically in battle can say, "violence is glorious," or "we are the most noble in the worst of times." The death of civilians can say "war is a pointless and indiscriminate killer of the innocent," or "War is justified to protect civilians from such barbarians as these."
- You can, of course, get literary, and have the death of your MC reinforce the point you're trying to make in your story. If your story is about the pointlessness of life, then being murdered at the end fits (but could anger readers not expecting a literary novel).
So ask yourself, "What is the most meaningful thing to the person dying?" and, "What is the most meaningful thing for the people that survive?"
- A variant on this is, of course, the "when is death not a death?" People can survive impossible dooms in weird and unexpected ways. I had a character who was nearly un-killable (but didn't know it) and "died" several times while still managing to be alive. But then each time, I had to make the event special and meaningful in different ways. Once as atonement for sins, once to get revenge (with consequences) and once to save their beloved. It's the willingness to die, in this case, that's significant.
Unfortunately, what would be a "good" death to a character is a hard thing to nail down. Handling death from cancer can be deeply meaningful and make a character ennobled even if it isn't self-sacrifice. Symbolic death can be very significant. If you've read/watched The Lovely Bones, the character is already dead, but the "death" they endure is in giving up attachment to our desires for something greater. In the end, the best death a character can have is in offering up what they thought was most important (typically life, but sometimes ambition) in exchange for what they realize is truly important (survival of the world, family, love, or sometimes just the one chance at experiencing life). But what that thing is will be specific to every character.