When writing, my tendency is to come up with a basic premise first, then try to figure out the most satisfying plot that would execute that concept.  

Premise: a woman’s peaceful life is disrupted when she receives a series of mysterious packages.

Premise: police find a dead body buried in a backyard, but things are not as they seem.

Premise: a woman is paid to make a dramatic appearance at a man’s funeral, but then doesn’t show up.

Each of these premises was a starting point from which I wrote a short story.  And for each concept, my first step in crafting the plot was to ask myself, which is the most likely situation in which this could happen, and which is the least likely situation in which this could happen.  

Which is the most expected way for this story to end, and which is the most unexpected way for this to end.  The most obvious answer would be boring but the least obvious answer could be unbelievable.  How do you balance those two extremes?

For my mysterious package story, I chose the most likely antagonist, a disgruntled ex-boyfriend, but deliberately brainstormed ways for that the story to end unexpectedly.  If the reader was expecting the ex-boyfriend to eventually show up and resolve the plot, how could I turn it towards a different outcome than some Lifetime woman-in-jeopardy story?

For the man with the dead body in his backyard, I decided the plot should either be about a suspect who is proven innocent, or a seemingly innocent person who is found to be guilty.  Which character would be more interesting and what would have to occur to flip the investigation in the opposite direction?

For the woman who fails to show up at the funeral, I initially decided that the best starting point who be for the protagonist to be a model/actress — a woman who is paid to be pretty — who then suffers Faustian consequences for her decision.  However, after nearly finishing my first draft I realized that an ambitious Hollywood type simply wasn’t an interesting enough character to drive the plot.  It wasn’t the story I wanted to tell.

Starting back at square one, I needed to think of a woman who could find herself the subject of a Faustian offer, but not be the most obvious person to receive the offer.  What is a scenario where a normal, beautiful but non-model woman, could receive an unusual offer and not immediately dismiss it out of hand?  

I thought of my former co-worker who had a public-facing job and would often receive attention from random dudes who found her attractive.  What profession, easily identifiable to readers, would put a sympathetic woman in a public space where a mysterious man could approach her with an irresistible offer?  Low-paid customer service at a high-end business.  A concierge at a hotel.

Fortunately my failed attempt at making a model/actress into an interesting character gave me a headstart in developing the hotel employee character.  It helped me realize that the protagonist needed a more compelling reason to accept the offer.  It also helped me realize that one of the themes of my story was beauty and how women deal with it.  

Those two conflicts gave me fuel to generate interesting plot points that would lead me to the ending of my story.