When I was about twenty years old (1978), I found a great book at the library on soft furnishings. It had big lips and fluffy things and pictures and all of the weird and wonderful cushions imaginable. I got it out again and again and was inspired enough to make my own funky designs.
Cushions should be cosy, in my humble opinion, and I invariably end up using velvets. Almost invariably. Making a new set of cushions changes and lifts any interior beautifully. Forget a new paint job or a new house or an extension, just make some new cushion covers! Easy.