Today at The Writer's Coffeehouse, one participant asked, "How important is research?"
Well, a lot. Exactly how much depends on your genre. You can make up a lot if you are writing about civilizations on alien planets. If you're writing historically based fiction (the guy asking the question was working on a story about a gunslinger) you need to be more conscious of world that you are representing.
So in the case of a story about a gunslinger in the Old West, you want to have a decent general understanding of the world in which your gunslinger is wandering around, and a better understanding of the details that would be important to the POV character. So, know what a glass of beer costs, what people wore, the architecture and terrain and weather in the area. And then - learn a bit about what's involved in firing and cleaning and wearing a revolver.
The small details are what flesh out your world, what make it live and breathe, but don't infodump. First, infodumps are boring. Also, they are dangerous. Each detail is something you can get wrong. You need to find the right balance for your story, the right amount of detail, and then be accurate with your details.
Important - don't count on what you know. Because (if you have watched TV or Hollywood movies or read any popular novels to any extent since, oh, the start of the silent movie era) what you Know is flawed.
Example: Navy boats have radar. We all know this. I wrote a story - WWII battleship vs a sea monster. Showed my dad. He said, "Are you sure radar was invented yet?" Um. Apparently at the start of the war, not really. The first successful trial radar system was installed on the New York the same year that WWII broke out. Fortunately for me, my story took place mid-war, on a pre-WWI battleship that was overhauled in 1942, and radar was in general use on larger ships by then.
If I had had radar on my ship at the beginning of the war, I'd have lost everyone who knew about these things. As someone at the meeting mentioned - as soon as a reader sees something that they know is wrong, it pops them out of the story, and as hard as they try to get back into it, there's a part of them that won't trust your details.
So, if you're writing a gunslinger story set two years after the American Civil War, you can't have him draw his Colt 45. Civil War ended 1865. Colt 45 was introduced in 1873. Your gunslinger is gonna be using a different gun. The gunslinger's gun is important to the gunslinger, so you can't leave out or fuzz this detail. You have to get it right. I'm not the guy who'll catch inaccuracy in firearms details. But there's a lot of people out there who will, to whom that's important knowledge. Get that detail wrong and you risk losing them. Get it right, and it'll get their attention the right way.