The basics of journalism (the 5 W’s & 1 H) apply to fiction, as well. If we don’t know who, we won’t care about the rest.
Write long, & then cut it down. It’s easier to have plenty of material to work with than it is to have to “pad something out” to reach the word count threshold.
It is better to take the time to write a new story than to butcher an existing one to fit in a certain word count.
Your characters don’t have to be realistic, if they are representations of real ideals (such as in Ayn Rand’s The Fountainhead).
Writing an analysis of your short story can help improve succeeding drafts, enriching it with symbolism (& making sure all the elements make sense).
Writing is an art, editing, a science.
You will learn more from one character in real life than you will in 140 on Twitter.
If you can’t remember the characters’ names in a book, it wasn’t a very good book.
Plot-based books often get read once whereas character-driven novels get read again & again. Character matters.
A minor character can have a significant impact on a major one.
You don’t have to write linearly. If you have a scene in mind that you’d like to go ahead & write, do so. It doesn’t matter how you put the puzzle together, only that it makes sense when it’s finished.
Don’t self-publish until you’ve had your manuscript professionally-edited. Just. Don’t.