Getting multiple patterns to match is about scale but its also about similarity in the shapes of the designs.

In your inspiration photo, all of the fabrics used have diagonal lines and also are of different scales. The black and white chevron is large while the black and white sheet print is small.

It is also about color. The comforter, the sheets, the chair upholstery and the curtains are all black and white. This helps keep the look unified without being too "matchy-matchy". The other items are all purple.

There are three only colors in the room: purple, black and white. But it surely looks like more doesn't it? It's because the patterns add so much interest!

Some suggestions: Paint the wall behind your bed the dark grey from your inspiration blanket. Look for sheet set in black and white smaller print. Comforter/duvel could be solid black or white or purple or patterned if the pattern is large - like the inspiration photo. Do think about keeping one of the items a solid - just as the purple blanket in your photo - either the duvet or the sheet set. It provides some "rest" for the eye. Otherwise it begins to look a little too chaotic.

Look for diamonds, triangles and other diagonal lines. Avoid circles. Find a couple of toss pillows in the dark purple in your blanket for more accent color.

Painting the wall dark grey is a commitment but it is also a neutral so that if you tire of the purple and royal blue combo in your Pendleton blanket, you could easily switch to some other color scheme.