General World Building Research Advice

First of all, write down what you already want for your imagined setting. It just has to be a few details such as architecture, climate, flora, or fauna. Then hit the books. Find real-world locations that have these things and research them to learn what climate influenced those flat-roofed adobe houses, what sort of history / environment encourages collectivism, and what sort of landscape suffers a lot of thunderstorms.

You might need to tinker around with your ideas once you find the facts, though. Those flat-roofed adobe houses aren't going to last long in a tropical land filled with heavy rain or even a cold area full of snow so you might need to make choices. Does your inspiration for architecture stay? Or your first choice of climate?

Of course, researching only the country most superficially similar to your Imagined Land may lead to the Cut-and-Paste mentality. This is where fantasy authors who do not wish to do either an urban fantasy or an alternate Earth-style fantasy, simply copy a single country whole-sale. The most obvious examples for this are England, Ireland, and Japan.

So if you're using a climate / architecture similar to Mexico, also look at other countries which share similarities with what you're going for. Even a brief read through of a few books, encyclopedia entries, or web-sites, can give you fresh inspiration for how humans might function in such a land.

Now you have done your foundational research, what are looking at the other cultural issues and catastrophes. How have other countries reacted to plagues? What sort of history / religion have set up caste systems in other countries? How has the industrial era affected different countries?

If this sounds like a lot of work, well, it is. You don't have to spend that much time world building. You can either create an alernate-earth-style fantasy setting or you can simply let the culture bloom in your mind. Still, research does help, is a lot of fun, and can inspire you to see the world (both real and the imagined one) in a different light.