This is a question I think every writer has asked themselves at one point. I don’t think there is a right or wrong answer, though there are most likely more logical answers. I liken it to the age old question: Which came first–the chicken or the egg?
When it comes to my own work I tend to rough out the plot first (to some degree) as it allows me to figure out what types of characters I want (personalities, beliefs, etc.) and why they fit in that particular story. There are plenty of writers who come up with characters first and then sit on them for weeks, months, and years until they can come up with a story, and that’s absolutely fine, but I’ve found I write characters better when I know the general plot. This is something I learned firsthand when I started my novella, The Walker and the Doe (see The War Against).
After plot, I work on setting next. I’ve got the details down, the story structure, now I just need to figure out a place in which to drop it. Coming up with the setting, whether a booming city or a lush forest (or maybe a swamp), after the plot helps me tailor my characters to that story. If they live in a city, are they angered by political unrest or weekly murder? If they live in a forest, do they seek the trees for solace (maybe even a run to the plains?) ?
When it comes down to it, there is no wrong or right way to writing a story. I think it comes down to preference and comfort. If it’s worked for you in the past, why not continue what you’ve been doing? Or, if you like a bit of fun, change the routine up!