Find where the belt wants to sit

Put on the loose layer and let it fall naturally before adding the belt. Decide whether you want to suggest a waist, hold a cardigan closed or simply introduce another colour or texture. Those are different jobs, so the belt does not need to be tightened to the same degree for each.

Try a comfortable position, then move it slightly higher or lower to compare. A dress's existing seams or a cardigan's pockets may guide the choice. If the belt cuts across a bulky pocket or fastening, shifting it can make the fabric sit more easily. You do not have to place it at a point dictated by a generic proportion rule.

Arrange the fabric without overworking it

Allow some cloth to remain loose above and below the belt. Pulling every fold flat can turn a relaxed garment into something strained. Look at the back as well as the front to see whether a large amount of fabric has gathered in one place.

Try sitting and reaching. The belt should leave you able to move without pulling the entire layer out of position. If it repeatedly rides up or slips down, the fabric, belt width and position may not be a comfortable combination. A narrower or softer belt can create a different result, but removing it is also a valid choice.

Keep the rest of the outfit readable

A belt becomes one of the visible horizontal lines in an outfit. Notice it beside a neckline, skirt hem or jacket edge, then decide which feature you want to notice first. A belt close in colour to the layer can be quieter; a contrasting one can become the focus.

Check any buckle against jewellery or hardware only to the extent that it matters to your eye. Exact metal matching is optional. What matters more is whether the buckle's size and shape feel appropriate with the softness or structure of the clothes.

Before leaving, see how the arrangement behaves under a coat or bag strap. If the belt makes adding outerwear uncomfortable, it may suit a day when the layer is worn on its own. An outfit change should fit the day's movement as well as the mirror.