Mixing designs and textures
To make the scheme interesting try mixing stripes, checks and florals in neutral tones. For example you could choose a floral as a curtain material and then have a selection of cushions in checks and stripes. Another option would be to use velvet as a curtain fabric, this would create a luxurious feel and add another texture. Woollen throws are a great way of adding more texture to a living room or bedroom. Upholstered furniture could be plain or why not introduce a tartan chair to introduce a statement piece into your room.
Flooring is best kept plain but could be carpet or wood with a rug added for warmth and texture.
If you want to add just a splash of colour, you could introduce this as a bold piece of artwork. You could also add a bit of sparkle by having a gilt mirror or embellished throw.