The south western region of the United States is all about Spanish & Mexican blend of cultures (though each have their shares distinguished), desert locales and a plot for many big time classic flicks. If you wish to decorate your room in a similar fashion, you need to do a thorough research of the native trends. You can add bright colors & elements like turquoise, beige, pink & red to illuminate the theme. You will have to opt for wooden or clay components, as against the new age trends. Wooden tables with brightly colored tops go well with the theme and should be coupled with leather seating.
The picture frames should include south western elements or plots like horses, desert wildlife and so on. The artifacts can be of native American style, like the Kokopelli. Hand crafted accessories like baskets & pots made by the native Indian artisans will surely lighten up the place.