I remember when I began to get serious about writing. I was in my early twenties. One of the things that really worried me is would I have enough ideas for stories? It worried me. At the time it only seemed I had one or two ideas worth developing. It didn’t look good for the long term prospect, haha.
But I will tell you a little secret only writers know. Ideas are a dime a dozen. Taking those ideas, and shaping them into a story, however, is the harder part.
Ideas are just that. Ideas. They have no story, no characters, no theme, nothing,. You can’t sell an idea as a story to an editor. No editor in his right mind will buy an idea from a writer. They want stories. Here’s an example of a classic idea:
1. Boy meets girl.
2. Boy loses girl.
3. Boy gets girl back.
That is a classic story. It’s been around forever and it will be around forever. It has deep atavistic qualities which gives it staying power, I suspect. But it’s only an idea. It’s not a story. You have to flesh everything out. Do all that, change a few elements here and there, and you come up with:
Old Yeller.
That’s right. Old Yeller is a “boy meets” girl story changed into a “boy meets dog” story. And the real strength of the story? It’s a “boy meets something” story that is a lead-in to an even stronger story theme: A boy grows up to be a man.
That’s the true theme of Old Yeller, how a boy grows up to be a man. But it started with the simple idea of “boy meets girl” changed to “boy meets dog, boy loses dog, boy gets dog back.”
That’s what we do as writers. Ideas are easy. But when you get your idea how are you going to develop it into a memorable story that says something about human character? Ideas are easy. The writing that comes afterward…that takes a little more doing.
Hoover's Corner 
Love your using Ol Yeller as an example of changing around the “boy-meets-girl,etc.” idea. Human character traits become personified, animated, robotized, serialized–and on and on. The joys of writing!
yep, I agree