For almost four decades, the most reliable fashion show in New York happened on a sidewalk. Bill Cunningham reported for The New York Times from 1978 to 2016, and his station was the southwest corner of 57th Street and Fifth Avenue, where he caught people on their way to work, to shop or to lunch. On July 6, 2016, the city temporarily renamed that corner after him. He covered the rest of Manhattan by bicycle in a blue workman's jacket, which tells you most of what you need to know about NYC fall outfits: they are built for moving.

The trench coat does the most work here. Thomas Burberry invented gabardine in 1879, and the classic trench is double-breasted with ten front buttons, wide lapels, a storm flap and a self-belt. It was always meant as a rain and wind layer rather than a winter coat, which is exactly why it suits October in the city: one layer for drizzle, a sweater underneath when the wind picks up.

In our fashion dreams, she is crossing Fifth in the Maison Mayle Eterne trench in tan, belted with the collar up. If you want the textbook version, the Róhe Classic double-breasted gabardine trench in beige follows the original almost line for line, and the Burberry Camden in organic cotton gabardine keeps the shape a little cleaner. The Totême Garderob in black is the city answer, since it hides subway grime and looks right over a slip skirt at night. For something less expected, the Nour Hammour Marchand in chocolate and the Kallmeyer Dorothy in green both read as a trench from across the street without matching everyone else's.

One test before you commit: button it all the way and lift your arms as if you are grabbing a subway strap. If the back pulls across the shoulders, size up, because you will want a sweater under it by November.

Washington Square in late October is my favorite place to watch how New Yorkers layer. The answer is almost always a sweater fine enough to sit under a coat and interesting enough to wear alone once the coat comes off. Picture her cutting under the arch with a coffee in the Giuliva Heritage Arianna turtleneck in burgundy, slim blue jeans and sand suede boots, which is about as autumn as a color story gets without trying.

For texture, the Loulou de Saison Tristan in gray is a yak and wool blend with a soft, slightly hairy surface, and the Isabel Marant Thomane in brown is alpaca, so it has that halo that looks great against a camel coat. The Éterne Francis in forest green is cashmere and quieter, the one I would pair with dark denim and a black trench for dinner downtown. If you run cold, the Kallmeyer Domi turtleneck in brown is merino and cashmere and sits close to the neck, so nothing gapes under a collar.

A quick test: pinch the knit at the elbow and let go. If it springs back, it will survive a season of being shoved into a tote at lunch.

What I would skip: a chunky cable under a fitted trench. Save the Róhe cable-knit in cream for an open coat or a Saturday when the coat stays home.

Walking is the real dress code in this city, and jeans are what most people walk in. The woman I picture holding the pole on the downtown train is in the Nili Lotan Tribeca barrel-leg jeans in mid denim, a cream cable sweater, a long chocolate trench worn open and black ankle boots. A barrel leg needs a longer coat to balance it, and a trench is exactly that.

If you want one pair that goes with every coat in this edit, the Agolde 90's Pinch Waist and the Slvrlake London are both high-rise, straight and dark, so they sit cleanly over loafers or boots. The Khaite Danielle in blue is slimmer through the leg and made for tucking into a boot, and the Frame Ruler in mid denim does the same job with a little less fuss. For something lighter, the Still Here Everyday straight leg in white looks sharp with a black trench in October, and the Jamie Haller wide-leg in light denim is the weekend pair.

Before you commit, sit down in them. A front rise that digs in on a chair will dig in on a forty minute train ride too.

What I would skip: anything that pools on the ground. City sidewalks and wet hems are not friends, so aim for a length that just grazes the top of your shoe.

Every outfit in New York gets judged by its shoes on the subway stairs, usually by you. Imagine a Brooklyn stoop on a Sunday, bodega flowers in hand, in the Aeyde Aldous suede penny loafers in chocolate with white straight jeans, a brown alpaca sweater and a black trench thrown over the shoulders. A brown loafer warms up an otherwise cool palette.

The Church's Shelby loafer in tan is the classic, polished leather with a sturdy sole that looks better the more it gets scuffed. The A.Emery Lane suede loafer in brown is softer, good for a day with a lot of walking, while the St. Agni Minimal and the Studio Nicholson Donovan, both in black, are cleaner and squarer and made for trousers as much as denim.

For colder days, the Staud Wally and the Nili Lotan Joplin are both black leather ankle boots that work under a straight leg, and the Stuart Weitzman Stassi in sand suede has a slim heel for nights out.

A test worth doing at home on carpet: walk on your toes for ten steps. If your heel lifts out of a loafer, it will happen on every step down into the station.

What I would skip: pale suede on a rainy forecast. Keep the sand boots for dry evenings.

Nobody in New York goes home between work and dinner, which is why the tote is the hardest working bag in the city. It has to swallow a laptop, the sweater you took off at noon and probably a paper bag from the bodega. On our dream walk down Fifth, it is the Demellier Stockholm midi tote in black textured leather, carried by its handles, and it holds its shape even half empty.

Suede is everywhere this fall and it earns its place. The Liffner belted tote in brown and the Totême belted tote in black both have a strap that cinches the shape, the Staud Christos in brown suede has leather trim along the edges where bags wear first, and The Row N/S Park in brown is tall and narrow, so it sits close under the arm on a crowded train. For the office, the Victoria Beckham Victoria Soft tote in gray leather has a cleaner line, and the St. Agni woven tote in brown adds texture without adding another color.

Check the handle drop before anything else. If it does not fit over your shoulder with your trench on, you will end up carrying it in your hand all day.

What I would skip: a pale suede tote as your only bag. The Studio Nicholson Reflection in beige is lovely, but give it a darker partner for wet weeks.

If I were building NYC fall outfits from scratch, I would go in this order: a trench that fits over a sweater, one pair of straight jeans in dark denim, a loafer you can walk in all day and a tote with a long enough handle. The sweaters and boots come after, once you know what the coat looks like.

Then I would do what Bill Cunningham did for almost forty years and walk. The corner of Fifth and 57th is still there. Wear the trench, take the long way and see what everyone else has figured out. If you want to keep browsing, I also put together Sandals you Can Walk Miles In and Wedding Sandals You Can Actually Walk In.