When I’m looking at a story, one of the simple things I look at is setting. There are so many aspects to setting, so let’s just look at a few:
1) Is your milieu intriguing? Many authors will set a story in the most blasé of places. Often, the story is set “somewhere in the USA”. While for certain types of stories this may be completely appropriate, in most cases it’s not. It’s as if the writer has suffered brain death and couldn’t bother to come up with a real milieu. In most cases, it helps if you choose a particular place to set your story, and a particular date.
2) Is the world fully created? If you’re using a real-world setting, then “creating” that world is a matter of capturing it—learning its history, culture, and future. It’s not enough just to research a setting, you have to know it, get it into your bones. This usually means that you must travel to that setting and spend some time there. You can’t just blow through Amarillo, Texas and expect to really know the place.
In a science fiction tale, if you want to set your story on a planet, then creating a setting might require you to decide what kind of star system your planet is set in, along with the planet’s composition, rotation, axial tilt, number of moons, type of atmosphere, and so on. You may have to think about how to create alien life-forms, and develop their life-cycles, and perhaps create their histories, languages, and societies. Just getting those kinds of details takes some concentration.
If you’re creating a fantasy world, then you may have to look even further—into creating the flora and fauna of your world, along with cultures and subculture, the magic systems and economic systems, societies, languages, histories, religions, and so on.
So I look at how robust your setting is. I consider how fully developed it is. I ask myself, “Has this author put enough thought into the setting to create the illusion that this is a real place?”