How on earth do you get established in this unforgiving, ill-paid but ever-so-slightly glamorous profession? If you luck out, you might win an anonymous competition, as Richard Rogers and Renzo Piano did when they landed the Pompidou Centre in Paris while in their thirties. Rogers has been evangelical about competitions ever since, as well he might. But what if they hadn't won? Would we ever have heard of them?

Well, yes we would, because Rogers (pre-Piano) was in a fashionable if impoverished outfit known as Team Four along with a certain Norman Foster and their respective architect wives. They were making small waves. Were there such a thing as a 40 under 40 show in 1965, say, Team Four would have been right on the money. Foster was only 30, Rogers 32, they'd done a few modish houses and were about to design the first modern English high-tech building, a now-vanished factory in Swindon which they somehow managed to invest with an aura of right-on, left-of-centre chic. So if you bet on Team Four in 1965 you'd have been well rewarded. But what of 2005?

It is happening now because this is an anniversary: 20 years since the first British 40 Under 40 show happened in 1985. There was another in 1988, then they stopped. At the end of the 1980s, it seemed as if every young architect in the country was being sucked into huge commercial firms to churn out post-modern shopping centres and speculative office blocks. Then came a deep and lasting economic recession, so they were all thrown out of work anyway. But as with Live Aid, a good idea will always be revived by misty-eyed nostalgics, and since British architecture has improved more than somewhat since the 1980s, why not?

The 1980s shows contained a lot of people who turned out to be merely ordinary, some who vanished altogether, and a few who went on to become really rather successful. Such as Will Alsop, or David Chipperfield, John McAslan or Amanda Levete of Future Systems, neo-classicist Robert Adam and so on: architects who are now in demand internationally and are just about as stylistically different from each other as it is possible to be. You could say that the 1980s failed to yield a new Rogers or Foster, though Alsop (who had, amazingly, come second in the Pompidou Centre competition as a 23-year-old student) is the one who has flown closest to megastardom.

Architecture being the longest of long games, reputations wax and wane. Death only starts a series of reassessments. Lutyens vanished for years, Le Corbusier went through a period of being reviled, Mies van der Rohe's attempts to work with the Nazis have never quite been forgotten, Frank Lloyd Wright has had more ups and downs than a Frank Gehry building. So what chance of spotting a future star at 40 under 40?

Well, here are a handful to take note of, and if they let us down in future years, don't blame me. There's Cécile Brisac of Brisac Gonzalez, for instance, who has had her own Pompidou moment in the form of their competition-winning Museum of World Culture in Gothenburg. When she and Edgar Gonzalez won that international contest, she was just 30. It opened last year and looks very assured indeed in a Rem Koolhaas-influenced kind of way. To have a £27m building like that under your belt early in your career is no mean feat.

There's David Adjaye, who has been fashionable for what seems like so long as a designer of oddly-textured homes and imaginative low-budget cultural buildings that it's something of a surprise to find he's still under 40, or interested in appearing in this show. Adjaye is a successful architect with flair and star quality. His extension to Denver's Museum of Contemporary Art may give him global impetus.

Consider also the larrikin outfit known as FAT - standing for Fashion, Architecture, Taste. Sean Griffiths, Charles Holland and Sam Jacob of FAT have had a huge amount of fun dancing around the edges of architecture and public art, promoting their brand of post-modern revivalism. Go to Grifffiths' Blue House in Hackney, however, and you find a cleverly-conceived and wholly practical sequence of domestic interiors behind the surreal manifesto façade. They're plainly very good architects: time to stop mucking around. If they got over the FAT thing and re-emerged as soberly-named Griffiths Holland and Jacob, they might become a force in the land.

You might not have heard of Hakes Associates but this husband-and-wife team, who used to work for Sir Michael Hopkins, could turn up trumps. I like the look of their Wycoller visitor centre in Lancashire, but it is bridges that they are getting known for. Their Mobius Bridge, intended for Bristol's Floating Harbour, based on the endless Mobius Loop, gives a flavour. Looks like established bridgemasters Wilkinson Eyre have got themselves some competition.

And then there is Surface. Good name, good architects, lovely eye-searing website, though like too many of their kind they are inclined to over-intellectualise what it is that they do (I have endured a toe-curling lecture from them before now). Don't try to talk or write, chaps, just get on with producing really impressive work such as your projects for Queen Mary College. Surface are able to make even a dull commission for a lift and disabled toilet at the college's medical library into a totemic, mysterious structure. And when extending a Victorian lock-keeper's cottage into a graduate Humanities centre for the college, they just went a bit mad and produced an asymmetrical crystalline structure that somehow works just fine in the context. Surface deserves to get a seriously big commission somewhere - maybe a factory or hospital or suchlike architecture-starved building type - and see what they can do.

Playing the fame game, getting in the right glossy magazines and having the right friends and relations is one time-honoured way to get on as a young architect. Another, luckily, is just to do good work. To find a client, as Richard Rogers and Norman Foster did with Peter Parker and his factory in the mid 1960s or as Graham Haworth and Steve Tompkins did with the Royal Court's Stephen Daldry in the 1990s, who is prepared to take a bit of a chance on his architects on the basis that they have talent and commitment end energy. Anyone can sign up a famous name. The clever ones are those who find you before you get that way.

The "AJ Corus 40 under 40" exhibition, sponsored by Corus and the Architects Journal, is in Gallery 50 of the Victoria and Albert Museum, London, until August 29, 2005.

See all 40 architects and their work at: http://www.vam.ac.uk/collections/architecture/temp/40_40/13772-lbox.html