Writers and editors often quote Stephen King's book On Writing in which he says, "Kill your darlings." Some writers new to the game may be scratching their heads.
"What does that mean?"
Let me start off by letting you know that Stephen King wasn't the first to say this. Killing your darlings has been recommended by many authors over the years, as far back as Sir Arthur Quiller-Couch (1863-1944). It is believed that Sir Arthur Quiller-Couch is the first to have coined this phrase, but instead with the words "Murder your darlings."
What this means is that anything unrelated to your story's overall plot needs to be revisited with unsentimental objectivity. You can lose your readers' interest if you stray too far off topic. No writer, or reader, wants that.
This can be as simple as omitting repetitive words or as heart wrenching as getting rid of a character altogether. If you have a character that does nothing to further the plot, or to help inspire the main characters with their roles in the overall plot, you may need to consider removing the character. A good question to ask yourself when considering killing a darling is: If I remove this character from each scene he or she is in, will it make a difference? If the answer is no, you should kill your darling.
It can also mean getting rid of minute details. I've read books that drone on and on about the description of a room, with nothing left to the reader's imagination. It pulls the focus from the bigger picture, derailing the audience's train of thought. Don't let this deter you from writing vivid descriptions; just make sure you don't overdo it.
If you can't bring yourself to kill your precious darlings, ask someone to read your story, preferably another author with equal or more experience than you—maybe someone who has had to kill their own darlings. Beta readers are also a great resource for writers. They aren't professionals. Beta readers are avid readers who give writers their feedback before a book goes to print. Their unbiased views can prove incredibly beneficial to an aspiring author.
The most important thing you need to remember is that you are not only writing for yourself. You are writing to please and appease your audience. Make sure you know who your audience is. For instance, if you're writing a crime drama, your audience is not going to be trekkies, and visa versa. Knowing who you are writing for is just as critical to the writing process as killing some darlings in the editing stage.