A pareo is a lightweight Tahitian garment that is similar to a sarong or wraparound skirt. It is basically a large rectangle of fabric. There are several ways to tie one to get different looks. You can wear it as a skirt or wrap it around your entire body so that it is more like a dress. The pareo is long enough to function as both and it will look fashionable either way. The most important thing is to tie it tightly enough so that it will stay put. You don't want to fall victim to a wardrobe malfunction.
Tie it into a halter-style dress. Open up the pareo and hold it lengthwise behind your back with one hand on each of the top corners. Wrap the pareo around the front of your body with the top seam at chest level. Bring the corner you're holding with your right hand to your left shoulder and vice versa. Pull the two corners behind the nape of your neck and tie them together.
Tie a backless dress with a blousy style top. Hold the open pareo lengthwise in front of you. Tie the two top corners behind your neck. Gather all of the excess cloth at your hips and pull it over to the left. Tie it in a knot at your left hip to make a tight skirt.
Tie a short skirt that is perfect for wearing with a bikini top. Again hold the pareo up lengthwise, but this time place the top seam at your waist. Take the two corners and tie them together at your left hip. Pull the knotted end toward your right hip so the pareo fits more securely on your waist. Hold the knot with your right hand and place your left hand on the fabric where it meets your left hip. Pull the fabric up while rolling it downward, like you would when folding over the waistband on a pair of sweatpants. Keep rolling the fabric until the bottom seam is at your knees. Make sure to roll both the front side and the back side. If it's easier, you can do them separately.