The line of the dress

The first visit to a boutique is rarely the pleasure it is supposed to be. The rail is long, the names blur, and somewhere around the fourth fitting the choices stop clarifying and start to overwhelm. The usual advice at this point is to work out which shapes suit your figure. It is the wrong question, and it puts the dress in charge of you rather than the other way round.

A more useful approach is to think in terms of line and movement. Every silhouette draws a particular line, and every line allows a particular range of motion. Decide what line you want to cut through the day, and how freely you want to move while you do it, and the rail shortens itself. What follows are the nine shapes you are most likely to meet, described on those terms.

The three you will see most

• The A-line. Fitted through the torso, then falling outward in a clean triangle to the floor. It draws a balanced, uncomplicated line and leaves you entirely free to move, which is why it is the most worn and the easiest to wear.
• The ballgown. A structured bodice above a full skirt. It defines a waist more sharply than anything else here and carries the most presence in a room. The trade is manoeuvrability: you will be aware of the skirt all day.
• The sheath, or column. Falling straight from the shoulder to the floor in a single quiet line. It is the most understated of the three and sits well in relaxed or informal settings, where its restraint reads as deliberate.

The cuts that follow the body closely

• The mermaid. Close through the bust, waist and hip, then breaking sharply into a flare at the knee. It draws the most dramatic line of any cut here. It also restricts the stride, so it asks something of you in return for the effect.
• The trumpet. The same close line through the hip, but the flare begins higher, around the mid thigh. It keeps most of the mermaid's drama while giving back a good deal of the walking room the mermaid takes away.
• The fit and flare. Sitting between the A-line and the trumpet. Close through the hip, then opening into softer, moving fabric. Of the close-fitting cuts it is the one built to be danced in.

The question is not whether a dress suits you. It is whether you can forget you are wearing it.

The shapes that step off the expected path

• The empire. The waist raised to sit directly beneath the bust, the skirt falling straight and soft from there. An old line, Regency in origin, that drapes rather than constricts and carries a particular lightness.
• The tea length. A hem that finishes between the mid calf and the ankle. Mid-century in feeling, less formal by nature, and the only cut here that leaves your shoes part of the picture.
• The suit, or jumpsuit. Tailored trousers or a single clean line of a jumpsuit, in place of a skirt entirely. The most modern option, and often the most comfortable, whether worn for the whole day or kept for a change at the reception.

The source of all the good advice on this subject says the same thing in the end, and it is worth repeating. The real test of any cut is how you feel moving in it. A line you admire on the rail but cannot sit, eat or dance in will work against you by the evening, a point couples make again and again from the far side of the day in looking back. Choose the line you want, then choose the version of it you can stop thinking about. Whatever you settle on, it sits on the wider list of decisions in the master checklist.