Give your attention to the visit
An afternoon in a gallery rarely needs a special costume. What it does need is clothing that stays comfortable while you walk slowly, stand in one place and move between rooms. Start with shoes you know and a bag you can keep close without repeatedly adjusting its strap.
Check the venue's own visitor information before packing. Bag restrictions and cloakroom arrangements vary, and a large bag may be inconvenient even where it is allowed. Carrying less can make it easier to move through a busy exhibition without worrying about the things beside you.
Choose a layer you can remove
Indoor temperatures may feel different from the street, especially after the journey there. A cardigan or light jacket gives you an option without requiring a complete change. If your coat will go into a cloakroom, make sure the outfit beneath it works as a whole.
A soft knit with trousers is one possibility; a dress with a loose outer layer is another. The useful feature is freedom of movement. You should be able to bend to read a label, sit on a bench and reach into your bag without pulling at the clothes.
Avoid making every accessory a project. A scarf that keeps slipping or a bracelet that catches on a sleeve can become irritating during a quiet visit. Choose one detail you enjoy, whether that is colour, a pair of earrings or the texture of a bag, and leave the rest easy to manage.
Think about the rest of the afternoon
If the visit ends with lunch or a walk, dress for that part too. An outfit that depends on remaining indoors may be less useful than one that can handle a short spell outside. Look at the forecast and consider the journey home before choosing an exposed shoe or a very long hem.
There is no need to match the style of the art, the building or the other visitors. Clothes that let you forget about them are often the most rewarding choice for a day spent noticing something else.
