There's just one rule for fall fashion: Keep it classic

Picture this: a classic, camel-colored trench coat worn with a skirt and mohair shell of the same hue. Or: mod, heather-gray joggers paired with a nubby pullover and cross-body purse.

Nice, right?

To elevate your look this fall, you need to incorporate only one color, print, or pattern into an outfit.

Just one.

The wisdom behind this is simple. One print is never too busy. One pattern makes an outfit automatically classy. And when flanked by layers of texture, one color story appears cool, calm, and confident.

"There is a sense of peace and security in the monotone story," said Bela Shehu, designer of NINOBrand, the 4-year-old women's-wear line out of Rittenhouse Square.

"And although we've been enjoying lounging, we still crave luxury in our everyday lives. The more-educated consumer understands tactile and supple fabrics and fine yarns. Monotone denotes a certain richness."

At the same time, February's fall 2015 runways proved that established designers, from Nicole Miller to Michael Kors, were intent on making clothing that considered our busy lifestyles. Our daily grind brims with quick transitions, from work to gym to errands with kids.

Yes, there are a few balls and bar mitzvahs sprinkled into the hectic mix. But let's face it: We are doing more texting and binge-watching streamed TV from our couches than hitting the clubs - millennials included - hence, the growing numbers of casual, comfortable clothes that take us from day to night.

And yet, for the first time in several seasons, there are new basics to add to our closets of leggings and midi-skirts: fitted denim jumpsuits, hole-punched sweaters, dramatic capes, and fringed dusters.

"This is a sophisticated moment," said Donna Sandoz, owner of Erdon, with stores in Old City and Moorestown Mall. "It's all very feminine and wearable. People are responding to it."

Thank goodness, because even the most fashion-forward among us - including designers - seemed to have lost interest in mixing quiet polka dots with commanding plaids.

"I was trying on 25 things on any given morning," said Alicia DiMichele, owner of the eponymous boutique at the Promenade at Sagemore in Marlton. "My bed and floor would be covered with everything."

The last time fashion featured a similar monochromatic elegance was back in the late 1930s and early '40s.

Often referred to as the most glamorous era of the 20th century, these years had designers like Elsa Schiaparelli, Madeleine Vionnet, and Coco Chanel creating lean, soft-tailored silhouettes completely doused in navy, camel, olive, and black. Hemlines fell down, and the crazy mixing of patterns that was a hallmark of the Roaring Twenties got toned down.

Actresses Marlene Dietrich, Jean Harlow, and Ginger Rogers further fueled the trend with tweed skirts, silk blouses, and fur stoles - all featuring colors closely situated on the color wheel.

The economic climate of the era mirrored what's happening now, too: The country was recovering from the Great Depression. We've spent the last five years or so trying to dig out of the most recent financial debacle.

During this reinventing and rebuilding, the unabashed mixing of nearly everything seemed appropriate. Now, as we wait to see how those entrepreneurial gambles have paid off, we can taper off on the sartorial experiments.

"Our mood is cautious," said Ann Gitter, owner of Center City's Knit Wit. "We aren't pushing the envelope too hard right now - and that's OK."

The "athleisure" trend - sports-inspired women's clothing - also adds to the season's diversity of texture and gives a futuristic feel to looks from edgier designers like Alexander Wang, Hood by Air, and even Kanye West.

Those details include satiny perforations on sleeveless, silky, or cotton shells; stripes running up the legs of trousers; patches of reflective fabric on fitted, black blazers and neoprene dresses.

"The proportions are fitting a little closer to the body, and there is an athletic drape to them," Sandoz said. "People look good coming and going."

One color with lots of textures means less to figure out. But there's the danger of looking flat.

You want different variations of the same hue, like a navy skirt paired with a shell that features an indigo and slate gray print. Top that off with a blue blazer, and a midnight microsuede tote.

If you stick with the exact tone, go hard on texture. A pair of crepe skinny pants with a matching tunic layered underneath a leather moto jacket is smart. Add a wool hat in the same color for fun.

"The magic of monochromatic," Gitter said, "is that it makes you look your tallest and your fittest."