Imported from the US, the school prom, or ball, is a major event in the modern teenage calendar, much more of a landmark than school discos and dances were for older generations.

And for girls, finding the perfect outfit can be almost as much fun as the prom itself, with many researching and combing the shops for months in advance to seek out the perfect dress, plus accessories. Some are even getting a dress made. Then there's the hair, the make-up ...

"It's a rite of passage for girls now," says designer Dawn Stretton, whose shop in Leeds city centre specialises in chic and unusual outfits for big events. "Girls come in with their grandparents, their parents, boyfriend, sister - it's like a family outing, and it's getting bigger and bigger."

School proms and balls fall mainly between May and July, and the main prom hunting season starts in February, with girls coming from all over Yorkshire to her shop. She keeps a Prom Book, with details of which girl is wearing what to which prom, and some schools, she points out, have regulations - for example, no skirts above the knee.

This year, there is no one look regarding length - there's short, long and everything in between, although taller girls do seem to be favouring long.

Over at Harvey Nichols, BCBG Max Azria is uber-chic but less pricey than many designer labels and so is popular with teenage fashionistas, while shops such as Emma Somerset and independent designer boutiques can also offer exclusive or limited designs to teens whose parents are prepared to fork out for their daughter's big night - increasingly, many are.

For more affordable looks, the High Street has some fabulous dresses in silk and satin, chiffon and lace, with exquisite details (see Six of the Best Prom Dresses). Check out Coast, Monsoon, Warehouse and Principles, and Designers at Debenhams. Try the Kate Moss at Topshop collection too. Yes, someone else might be wearing the same dress, but clever accessorising can change a look, funking it up or making it look classy. And does it really matter? No two girls will ever look the same, even in the same dress.

Having said that, the school prom is a rite of passage, marking the transition into becoming a young woman, so it is important to express individuality, rather than following the pack. It's an occasion to step out - in style.

Models: Charlotte Moulson and Hannah Moulson

Styling: Stephanie Smith and Charlotte Moulson

Pictures: Gerard Binks

Hair: Linda Garbutt at West Row, Thornton's Arcade, Leeds - 0113 245 6220.

Make-up: Famida Ayub at MAC in Leeds on 0870 192 5113

Fashion Assistant: Alex Haddow

Venue: The Sun Pavilion, Cornwall Road, Harrogate - 01423 522588

Dawn Stretton: 0113 244 9083
Harvey Nichols in Leeds: 0113 204 8000
Coast at Fenwick in York: 01904 643 322
Emma Somerset in Harrogate: 01423 502109
Morgan Clare in Harrogate: 01423 565709