A white sleeveless top. Everyone has one, it costs between nine and twenty euros, and that is exactly why it ends up worn the same way ten times in a month. The fashion industry lives off selling you a new piece rather than telling you what to do with the one you already own. This is the opposite.

Seven outfits, not one of them requiring a purchase. First: printed trousers. Lobsters, flowers, whatever - the pattern carries the whole outfit, and the white top is what lets it stop short of being too much. Second: chunky jewellery. A thick necklace in a strong colour, big earrings. The contrast between white and colour is more effective than any expensive blouse can manage.

Third, and the most unexpected: under a pyjama-set shirt. The summer version of that cut no longer counts as loungewear, and the top underneath means the shirt can also come off. One piece, two outfits.

Fourth: a sequinned or fringed skirt. This is the trick that saves the most money - the dressy skirt sitting in the wardrobe waiting for an occasion suddenly becomes wearable in daylight, as long as the top half is plain. With flats or sandals, depending on the plan.

Fifth: all white, with a simple white skirt. The cleanest choice at this time of year. With flip-flops or with thong sandals, the ones that came back from the nineties.

Sixth: denim or linen bermudas, for anyone who does not wear skirts. Relaxed, but not scruffy, if you add one strong detail - a navy or coloured bag. Seventh: capri trousers, especially polka-dot or striped. They are the ones that look the most expensive relative to what they cost, and the quiet simplicity of the white top is why they work.

The common thread through all seven is not the trend. The common thread is that the piece demanding the least attention is what lets everything else in the outfit speak. Worth knowing before the next shopping trip - and even more worth knowing the next time it feels like you have nothing to wear.