A beleaguered Microsoft knows the shortfalls of Xbox One all too well, and so it also knows exactly what to focus on and what to downplay - PlayStation 4 gives the green side a target to aim for.
For example, with resolution disparity stories dominating the games media for the last 18 months, it'd be wise for Phil Spencer & co to shift the focus away from multi-platform announcements and towards first-party exclusives this year.
But for Sony, success at the show is more intangible.
In order to stay ahead, it needs to imagine new targets to aim for, rather than locate them in its rivals. Sun Tzu probably has some interesting thoughts on the matter, but I simply can't bring myself to copy and paste them into an article about a videogames conference.
So instead, let's isolate what hasn't worked so well for Sony in recent conferences, and what it should have sold harder.
First and foremost on that list is indie gaming.
Sony hasn't so much told us that the PS4 is the home of indie gaming on current-gen as it has hog-tied us and jammed that sentiment down our convulsing throats, so it'd be wise not to lean too heavily on anything pixellated this year.
There's certainly a pocket of us who lap up games like Axiom Verge, Titan Souls, Super Time Force Ultra et al with nary a shred of prejudice for their 2D perspective or artfully arranged pixels. But there's also a contingent that sees these games as filler between triple-A arrivals, and takes to internet comments sections to decry that they 'didn't spend £300 for this' whenever a new title arrives, like it deliberately eschewed polygons just to screw with that person.
'Indie' is a nebulous term as it is, and you could argue any game getting a mention at a platform holder's E3 conference is forced to turn in its indie card then and there. Nevertheless, to create the kind of ripple everyone who watches the Sony live stream will feel, it needs to feature traditional triple-A titles.
It needs to feature them hard. And if you believe the time-honoured pre-E3 rumour mill, it'll have opportunity to do just that.
We already know Bethesda will be showing off Fallout 4, but the industry sewing circle has also thrown up possible reveals for Mafia 3, a new or remastered Red Dead title, and a new Souls game. Then there's Guerilla's mysterious new IP, 'Horizon,' leaked in 2014 and surely due a proper reveal. Any one of these can be conference winners, if Sony can wrestle the right to reveal them in its own presentation.
That Red Dead rumour is actually a perfect example of how the show can be won or lost.
The difference between a new game announcement and an HD remaster reveal is massive. Red Dead Redemption lies in the upper echelons of any gamer's remaster wishlist, but there's simply a cap on how excited anyone can be about a spruced-up classic versus a new and mysterious vessel for fresh experiences.
Thus, if Sony devotes any significant proportion of its conference to God Of War III: Remastered, it's not going to break the internet.
Recently Capcom announced a renewed focus on the HD-ification of its classic titles and Sony has also announced the stop-gap remastering of the Uncharted trilogy with the Nathan Drake Collection, so E3 2015 could well feature more of these announcements than any before it - the winning platform holder will be the one who doesn't get bogged down in it.
And, obviously, if there were so much as a screenshot of The Last Guardian in attendance, Sony has E3 sewn up. Even a phone camera picture of someone's desk at Team Ico with the screenshot on screen would do it, probably.
We can but hope.
Then, of course, there's Morpheus.
Sony's VR headset has the potential to be the most exciting thing in videogames, period. This writer's strapped one on, and found the experience genuinely transformative. As so many have said, it's not equivalent to the 2D to 3D transition in the '90s - it's more than that.
Dragging PS Move controllers back from the brink of absolute irrelevance is an incredibly smart move from Sony, and in fact it was these that most sold me on the experience. PS Move allows you not just to look around in the virtual space, but hold a virtual hand up in front of your face, rotate it with precision, and interact with objects in the world.
Here's the kicker - if I had a Morpheus headset right now, and a pair of Move controllers, along with 100% of the software Sony's demoed it with, the hardware would currently be gathering dust in my dungeon...er...basement.
There are only so many times you can stand in a pretend shark cage, barrel roll through space in a limited EVE Valkyrie demo and hack medieval mannequins to bits in the castle demo.
What Morpheus needs is a system-seller - a game, rather than a tech demo, to show off its incredible potential. Of course, Morpheus' potential goes well beyond gaming, but it's not going to win E3 with a fancy-pants VR version of Google Maps Street View.
If Sony can deliver that - a new triple-A title with full Morpheus support - the conference is won. No one else can compete with that.
Oculus Rift is an open platform, and while it supports peripherals which work in the same way as Move, Sony's is the more consumer-friendly, less bewildering proposition. What's more, within its first party studios are creators who seem perfectly suited to exploiting the new medium.
What on earth would Quantic Dream and David Cage do with Morpheus? I can't begin to imagine, but I'd play it in a heartbeat, no questions asked.
Likewise Media Molecule, who turned PlayStation 3 into a development platform for casual gamers; Ready At Dawn, who's consistently demonstrated its ability to squeeze a platform to the absolute limits of its tech, and Polyphony, who... well, I just really want to play Gran Turismo with Morpheus, in all honesty.
The take away then for Sony? Go easy on the indie, secure a big reveal, and ideally sign an exclusivity deal with it. Then show us a single feather from The Last Guardian.
But most of all, show us what Morpehus can really do in a gaming environment, not with a tech demo but a fully-fledged game. Do that, and it's yours to lose, Sony.