Poor Mick Jagger. He's attended one celebrity party after another, conducted endless publicity interviews but still his new solo album, Goddess In The Doorway, has failed to sell, shifting just 984 copies in its first day.

The Rolling Stones member is not the first to discover that hype does not always equal commercial success - just ask the makers of Hollywood blockbuster Pearl Harbor, the ill-fated Captain Corelli's Mandolin and the red-faced managers of the Millennium Dome.

Pearl Harbor, which was tipped to be the Titanic of 2001, failed miserably in the box office when it was first released in June. Despite the official budget being estimated around $150m, the film just did not live up to expectations. It was denied the top spot in the cinema charts by another less-hyped summer blockbuster, The Mummy Returns.

Likewise, Captain Corelli's Mandolin was given lukewarm reviews by critics and failed to reach number one in the charts. Even the fiery rapport between its leading stars, Nicolas Cage and Penelope Cruz, could not save the film and it only came in fourth.

The main product that most people would associate with over-hype would probably be the Millennium Dome. After a catastrophic launch and months of the Government regularly handing out more cash to finance the attraction, the Dome only managed to reach its target audience the month before it was closed.

Yet with all these flops about, is there anything you can do to guarantee a product enjoys commercial success? And when does hype turn into overkill?

Public relations adviser Max Clifford has promoted an endless range of celebrities successfully, generating amounts of media coverage, from entertainer Freddie Starr and Harrods boss Mohamed Al Fayed to Mandy Allwood, the Midlands mother who conceived and later miscarried octuplets.

Clifford says that the two main ingredients in promoting a person or a product successfully is timing and originality.

The Press love scandal and gossip so you have to think of an idea that the Press will approve of and give you maximum coverage, he says. For example, we launched David Copperfield in Europe a few years ago.

Claudia Schiffer became a crucial part of that campaign because she was one of the top models of the world gorgeous, glamorous, well-liked in the media and a big name in Europe while Copperfield was relatively unheard of.

I saw their meeting as the perfect opportunity to boost his career by making sure that she was seen with him constantly. This vastly increased the amount of Press coverage given to him than we would have got without her.

Clifford also has no qualms about using any situation to his advantage. When he works on promoting films, he tries to make events happen, which would add more Press appeal.

It would be brilliant if one of the main stars had split with their partner and this would be particularly poignant if it matched the film's storyline as well, he points out.

It is not all to do with timing. Scott Wilson, head of media at PR consultancy Countrywide Porter Novelli, says that a lot of research should be done into the product and its target buyers before the campaign begins.

Public relations is no longer an art but a science, he says. It is not about generating as much media coverage as you possibly can but whether you are hitting your target audience.

Initially, an agent should map out who they want to hit with the product. This is a process known as media mapping. Once they understand who their audience is and their needs, they can decide which medium is the best way to reach them. After this the appropriate people can be engaged in the campaign to promote their product and in turn, generate more media coverage through interviews and press conferences. Wilson believes that there is a challenge to public relations. The key to a successful PR agent is whether they are able to create publicity about someone or something that is relatively unknown. It is easy enough if your product or brand is already popular.

The same theory would apply to celebrities. Many famous people readily assume that they are given plenty of media coverage and this is probably where they are mistaken.

Wilson describes pure hype as generating coverage for coverage's sake.

He explains: The real value is the success of the product, not how much publicity has been created around it. Today's PR is all about delivering results we intend to increase awareness and in turn, increase sales of the product.

This appears to be true. Pure media coverage alone could not help films such as Captain Corelli's Mandolin or an attraction like the Millennium Dome.

Weeks before Captain Corelli's Mandolin was premiered, there was wall-to-wall coverage of the film with the two main stars being interviewed extensively in magazines and television programmes.

Just like the Dome. The public was bombarded with huge amounts of advertisements and promises that the Dome would live up to them all. Unfortunately they were wrong. The huge cost of the Dome did not justify the attractions inside and this was shown by the poor sales.

PR Week editor Kate Nicholas believes that this was due to an overkill in publicity.

When a product doesn't live up to its claims, it is killed in that the promotional work does not do the product little justice. It is extremely important that research into the product is necessary before the publicity campaign is decided on, she says.

The values of the product and its company have to match the values of the PR company. Only when this is ascertained, will the campaign be successful and sales will soar.