Put it where it does the most work
You rarely need a whole blue kitchen. The strongest versions of this scheme concentrate the colour low down and keep everything at eye level pale — blue base cabinets with white or off-white walls and open shelves, or a white kitchen with a blue island. It keeps the room feeling tall and makes the blue read as deliberate rather than overwhelming. If your cabinets are staying put, the same logic applies in smaller doses: a painted dresser, a run of blue-and-white tiles behind the hob, a blue table, or simply textiles.
Textiles are the cheapest and most forgiving entry point. Striped tea towels, a ticking-stripe blind, blue-checked seat pads, a tablecloth you actually use. Add a shelf of mixed blue-and-white ceramics — transferware plates from a charity shop, a Delft-ish jug, a chipped bowl that holds garlic — and you have the scheme without committing to a single tin of paint. A rented kitchen can do all of this and hand the keys back unmarked.
Warm it up or it reads as cold
Blue and white is a cool pairing, so the room needs something to hold it down: wood, brass, terracotta, linen, basketry. A wooden worktop or even a big wooden chopping board left out, brass or unlacquered handles that will dull with use, terracotta pots of herbs on the sill, a rush mat underfoot. One cheerful discordant note helps too — a bowl of lemons, a mustard-yellow enamel pan, a bunch of dahlias — because it stops the room looking styled.
