Nothing like a bold patterned fabric to brighten up white walls. Check out the curtains and the rug. Different patterns, but same color palette, thus a complimentary mix. I agree also with the furniture selection, a few colors from the curtain fabric, in subtle colors. Here the furniture fabric is a solid, but I think a small print or stripe would be great on the club chair. Love the small printed pillow in the chair, could use that print on the chair as well.
Using a large bold print in almost any room whether on a pillow, a throw, rug, or even a painting can be a fun strong statement.