Layering rugs is a great way of adding additional texture and colour to a room scheme. Placing a smaller statement rug on the top of a larger neutral one will create a frame for the smaller rug, increasing its impact. Colourful Moroccan rugs and kilims lend themselves perfectly to this idea. In this room (image courtesy of Apartment Therapy) a brightly coloured embroidered kilim has been used to define a dining area.
This is a really good tip for separating a large open plan living space into smaller areas for specific uses. You can still keep the look cohesive by making sure that the bottom layer rugs are all the same. Changing the top rug will instantly change the look whilst still maintaining the essence of the room scheme.
You can also layer rugs by just overlapping them slightly, placing them at right angles to each other. In this case pattern on pattern works really well. Nothing needs to match but you do need to choose shades and tones that work well together, although the design can be completely different. Be careful not to use rugs that are too thick, as this could present a trip hazard! Flat weaves are best suited to this idea. This image (also Apartment Therapy) illustrates perfectly how to do this. The stripes of the top rug are a really good contrast to the lozenge design on the lower rug whilst still picking up its ochre tone. The bright pinks in the stripes of the top rug also echoed in the cushion on the sofa.