Apple Inc. Chief Executive Tim Cook is expected to walk on a darkened stage and show slides on Tuesday in a bid to make some palm-sized objects look sexy.

Why? Because the presentation style perfected by Apple co-founder Steve Jobs may generate $300 million in free publicity from newspapers, blogs and television through coverage, estimates Yankee Group analyst Carl Howe.

The challenge for the tech industry is that now everyone else does a big slideshow launch, too. As the formula has become the tech industry's de facto tool for introducing new gadgets, the hard part for many is standing out. This month alone, gadget launches have been run or are scheduled by Apple, Samsung Electronics Co., Sony Corp., Qualcomm Inc., and Intel Corp. Oh, and one more: Microsoft Corp. on Monday announced it too would hold an event in September; the invite featured the logo of its Surface tablet.

At stake is a piece of the nearly $400 billion global market for smartphones and tablets.

'These events are about making a first impression, even for the biggest companies,' said Margit Wennmachers, co-founder of tech public relations firm the OutCast Agency, which helps companies like Amazon.com Inc. plan device launches. 'There's an incredible attention to detail because you don't want to seem canned, and that takes practice.'

OutCast client Anki Inc., offered a guest spot to show off its app-controlled cars at a recent Apple show, went through 'weeks of intense practicing' leading up to the event, she said.

Perhaps as much as the events themselves, Mr. Jobs's innovation was bucking the tech industry's previouslaunchtradition by avoiding the trade shows in favor of an Apple-only presentation. Doing so guaranteed exclusive media coverage and a concert-like atmosphere replete with devoted 'fan-boys.'

Among the conventions of an Apple presentation was Mr. Jobs's promise of 'one more thing,' before revealing a secret new product or feature, like an early Wi-Fi-enabled laptop or brightly colored iPods.

And while Mr. Cook has yet to command the same devotion, he has hewed closely to Mr. Jobs's style. He too paces a darkened stage and often saves the best for last. The few changes he's introduced are subtle: In place of black turtlenecks and gray New Balance sneakers, Mr. Cook wears dark untucked shirts and dark shoes.

'You have to try to make these devices larger than life,' said Mr. Howe. 'It's not an easy thing to pull off: very few, if any, companies are Apple.'

Still, many have tried to be. Microsoft last year borrowed from the Apple playbook for the introduction of its Surface line of tablets. Attendees only learned of the event's exact location hours before it was to start.

A recognizable CEO helps. Amazon.com evokes Mr. Jobs with founder and CEO Jeff Bezos as lone showman, pacing the stage in blue jeans and blazer.

For the launch of its Galaxy S4 smartphone in March, Samsung tried to reinvent the playbook, with unfortunate results. Hoping to capture buzz for its flagship handset, the Korean company concocted a Broadway-style revue held at 6,000-seat Radio City Music Hall, complete with dancers and a full orchestra.

The event, simultaneouslybroadcast to gigantic screens in Times Square, was punctuated by a tap-dancing child, riffs on 'Sex and the City,' and jokes.

Critics panned the show.

Samsung reverted to the more-familiar slideshow formula to launch its Galaxy Gear smartwatch and Note 3 smartphone earlier this month.

Spokespeople for Apple and Samsung declined to comment.

Even with the careful planning, these events can sometimes go awry. Mr. Jobs once threw a camera into the audience after growing frustrated when it wouldn't turn on as planned. And at a 2009 unveiling of the Kindle DX e-reader, Mr. Bezos appeared upset while technicians fixed an inverted image of the e-reading device on screens behind him.