Thanks. Going by his book, I'm not sure the plaid qualifies as SN. He says to use asymmetric and irregular curves (elongated ovals, wide circles, ellipticals, etc.). Relaxed geometrical with rounded edges. Easy swirls. Avoid: Sharp geometrics. Wide, chunky and boxy shapes. Overly ornate shapes.
On the skirt's style, however, it may be okay. He says skirts should have a soft outline. Full or flared skirts that are flat in the hip area are excellent. Straight skirts that are lightweight, draped, or slightly tapered are also good. Straight skirts have an even hem and are worn short, no longer than the bottom of the kneecap. Full skirts have an uneven harm and are worn long, mid calf and below. Slits, kick pleats, button fronts, plackets, etc. are all fine, as are bits of intricate detail (shirring, draping, etc.), as long as they're not restrictive. Avoid: long, straight, pencil-slim skirts. Overly fitted skirts with excessive trim. Symmetrical skirts (i.e., A-lines).