Is there a right and wrong way to plot out a story? What's the best way to get started?
Broad plotlines are best saved for books rather than short stories. A short story usually deals with a single plotline along these lines: someone has a problem and then solve it (or not). Some examples:
A man loses his lover and then gets her back
A wounded elf tries to get back to her village
A half-breed comes to terms with his hatred of his human father
Sometimes two plotlines are strung together. For example, with the "A half-breed comes to terms with his hatred of his human father", perhaps there is a second plotline where he can help a human survive or not. It's not until he comes to terms with the hate that he can look past it and help the human. This is a structure that works well: an internal struggle and an external one. It is not the only one, obviously.
So perhaps instead of a grand war, there is an individual struggle played out against the backdrop of the war. While mercenaries gather, for example, two children try to find a lost older sibling. Or a strung out addict tries to figure out where his next fix is coming from. A prostitute tries to figure out how to save up the coins to get to a larger, safer city.
That's my suggestion for plotting, at any rate. One thing that is helpful is to think in terms of scenes. Figure out the smaller story and the scenes that are necessary to tell it. Returning to the halfbreed scenario, you might need the following scenes:
An opening that introduces the main character and states the problem. Perhaps it also shows the dying human. It needs to be located in a physical place that is conveyed to the reader with more than one sense.
A scene that heightens the tension. Perhaps the dying human slips a notch, healthwise.
A scene that introduces a possible solution and then fails. You may want to have a series of these - a possible solution, a failure of that solution, another solution, the second solution's failure, and so forth. More than two or these of these and you risk lapsing into tedium.
A scene that introduces the actual solution. Perhaps he has a flashback to some human that was nice to him. Perhaps he sees someone treat someone else well. Perhaps he remembers his dead sister and realizes the human resembles them. Whatever. Again, in all of these, you want some physicality and to create a world that is interesting and engaging to the reader.
An aftermath scene. This is always optional, in my opinion.
