In Sulmona, the Abruzzo town known as "the city of confetti", the first confetti are traced back to the Emperor Tiberius in 37 A.D. In Italy the word means sugared almonds, not paper, and they still go home with wedding guests in a small tulle pouch called a bomboniera. Five almonds, always an odd number, because five stands for the indivisibility of the spouses. I like starting there: small rituals, done properly.

Dressing for them works the same way. What to wear to a wedding in Italy comes down to a few old rules. White belongs to the bride, and guests are told not to wear it unless the couple asks. A Catholic church wants covered shoulders and no miniskirts, and in Venice the shoulder rule is enforced at the door. At the reception guests keep the same dresses, with aperitifs poured while the couple finishes their photos, so one dress has to carry the ceremony and the long dinner.

Silk and satin midis are the easiest way to do all of that. I would reach for the Zimmermann silk satin wrap in rust pink first, because the blouson sleeves handle the church and the tie waist handles dinner. The Emilia Wickstead Capucine in crimson has long sleeves, a belt and a full skirt, which is a lot of wedding in one dress. The Rixo Lysandra in deep green, with its black lace trim, suits the guest who wants slip-dress ease. The Max Mara draped black and the Staud Phare in chocolate brown are the evening picks.

Short sleeves and thin straps, like the Victoria Beckham Bela or the Joseph slip, simply need a wrap in the bag. In the fitting room, sit down, lift both arms and kneel an inch. If the hem stays below the knee and the neckline stays put, it is ready for the aisle.

Zimmermann began in 1991 in Sydney, when Nicky Zimmermann designed garments in her parents' garage and sold them at Paddington markets. I think of that whenever I see the Indra, a peach and lavender printed maxi in a cotton and silk blend. It is the most playful dress in this group, with a plunging halter neckline and a cutout waist, so it is the one that most clearly needs a shawl for church.

Prints are where an Italian wedding lets a guest relax a little. The Etro pair is the obvious place to look: a navy long-sleeve maxi with a paisley and floral print and a keyhole neckline, and a yellow one with blue flowers and wide flowing sleeves. Both cover the shoulders without trying. The La DoubleJ Magnifico, a pale pink and olive silk twill with kimono sleeves and a floral border hem, is the one I would pack for a daytime ceremony.

For something quieter, the Veronica Beard Gemma in sage green has long sleeves and a slim bias-cut skirt. The Dôen Valerine in emerald floral silk satin has flutter sleeves, the Camilla in pink floral silk has tiered bell sleeves, and the Leo Lin Alice has a big painterly lily and rose print on navy.

Before you buy, check the base color in daylight. Anything that reads mostly cream under the print can look bridal in photos, and white in any shade is the one thing to avoid. Then walk a flight of stairs with the hem in your hand, because a maxi has to survive bridge steps and villa courtyards.

What I would skip: a print so loud it competes with the bride's day.

Floor-length and midi dresses are the safe choice at a Venice wedding, and an evening ceremony is where a gown makes sense. Long sleeves help too. They cover the shoulders for church and keep you warm when the light jacket would otherwise come out after sunset.

Solace London has two column gowns here. The Viviana is a deep burgundy with a high neck and sculptural satin ruffle cuffs, and the Olivia is a plum with a draped waist and a cape-style back panel. Burgundy and plum are jewel colors that sit well in an autumn wedding. The Victoria Beckham Florence is a black gathered jersey with a twisted ruched waist, which is easy to sit in through a multi-course dinner.

For print, the Erdem floral silk voile has sheer blouson sleeves and a high neck, and the Staud Freda in chocolate satin has dolman sleeves and a ruched waist. The McQueen draped satin in teal has one long sleeve and an asymmetric flared hem. The Jenny Packham Adella is a pale blue crepe with sheer embellished sleeves, and the Costarellos is mint georgette with ruffle cuffs.

In our fashion dreams, the guest in teal or plum crosses a stone campo at dusk with her hem lifted a little and a shawl over one arm. Ask whether you can lift your arms in it and whether the fabric moves when you climb a step. With a sheer sleeve like Erdem's or Jenny Packham's, check how much it actually covers before church.

What I would skip: a long train on a day with bridges.

Block heels between 5 and 6 cm are wide enough not to catch in stone joints, and that single line settles most of this shoe question. Italian towns and villa courtyards are paved in uneven stone, and one guide puts the practical ceiling for a block heel at about two inches.

The Jimmy Choo Faye is a black slingback with a square open toe on a 4.5 cm block heel, and the Gianvito Rossi Betsey is a silver metallic strappy sandal on the same height. For kitten heels, the Jimmy Choo Amelia is a dark brown pointed-toe pump at 35 mm, made from Italian-crafted leather. The Manolo Blahnik Maysale in brown suede has a signature buckle and a 50 mm heel, and the Gianvito Rossi perforated slingback sits at 5.5 cm. The Dolce & Gabbana suede slingback is 6 cm, so I would call it the top end for walking.

Loeffler Randall brings the evening shoes: the Rio in chocolate satin with a smocked toe and ankle strap, and the Dixie in silver metallic leather. The Rio has a leather sole with a rubber heel cap, which I would look for on any pair.

Test them on a hard floor at home before the trip, and walk on the ball of the foot as well as the heel. Many Venice guests carry flats in a small bag and switch to heels only inside the venue. That is a good plan for a long day.

What I would skip: smooth suede on wet stone.

Covered shoulders are mandatory for guests in any Venetian church, and it is enforced at the entrance. A wrap is therefore the most useful thing in the bag. Even if the ceremony turns out to be symbolic and outside a church, a shawl weighs nothing and the evenings are cool.

The Etro paisley jacquard shawl-cape in beige and black is a wool blend with a black border, and it looks like it was made for a big silk dress. The Row Keran is a soft green cashmere shawl made in Italy, with a draped, structured shape. Gabriela Hearst's Lauren is a powder-blue open-knit cashmere with long fringe, handknit by Manos Del Uruguay artisans. The Pleats Please Issey Miyake Madame-T is a lightweight pleated stole in a blue, lilac and teal print that would fold into a clutch.

For the bag, the Staud Muse is a small satin envelope clutch covered in multicolor beadwork, and the Manolo Blahnik Capri is a cobalt satin envelope with a crystal buckle. The Dries Van Noten is a small floral jacquard clutch in gold and green, made in Italy, and the Simkhai Morgan is a silver chain-link clutch covered in crystals.

Drape the shawl over a sleeveless dress and check it stays on when you raise your arms. Then see how small it folds, because it has to leave the church and live in your bag. The clutches here will hold a phone, a lipstick and a key, not a pair of flats.

What I would skip: a shawl so heavy it ends up on a chair all night.

I would pick the dress by the ceremony. Sleeves for the church, a midi or gown for dinner, and a color that is not near white. Then I would choose the shoe that can climb a bridge: a block or a kitten heel at 5 to 6 cm, with flats folded in a bag. If the wedding is on the coast instead of in a church town, I would also read the riviera chic dress code.

The wrap goes in last, and I would not leave without it. It is the thing that gets you through the church door and the cool evening after.

Somewhere in the evening, a pouch with five sugared almonds will land in your hand. Take it home. It is a nice way to remember that a good outfit, like a good favor, is small details done properly.