To understand what is Southwestern Decor all about, we must first understand where is the southwest? Southwestern in decor context basically refers to the Southwestern states of USA (Colorado, Nevada, Texas, Utah etc). As you may know, these states are basically filled with deserts and this "desert vibe" with a modern twist is what Southwestern decor is all about. Think Kilim rugs, taxidermy animal heads and loads of cacti...
Quick tips to this look
Colours: White, black & brown as the base colour with colourful accent pieces in rugs & cushions usually in shades of pinks, purples, red and turquoise.
Patterns: Kilim or aztec patterns is a must. Use this as your accent piece for the room. An easy way to incorporate this pattern is via a rug or a wall art (TIP: or you could hang the rug as wall art).
Decor elements: Kilim rugs (yes, I do realise I am repeating this, but it's basically THE item that makes the most difference), bull skulls / head as wall art (don't worry, there are plenty of chic fake ones available), cacti (the more the better, plus they help detoxify the air in your home), faux fur rugs, dreamcatchers and teepees which works really well in the nursery (and your kid will thank you for it).
Have fun decorating!