You take the best bits of a movie, chop 'em up, shuffle 'em about, and - like an estate agent's particulars - you order them in such a way as to make the film shine while hiding the dodgy guttering and damp patch in the kitchen.
Even Movie 43 looks passable condensed down to a minute...
And it was precisely because of the aforementioned shit-fest that was Movie 43 that I was apprehensive about I Give It A Year. You see, I'd rather enjoyed the trailer. It made me laugh.
And recent experience has taught me that this can't end well.
It helped enormously that I'd missed the fact it was written and directed by Dan Mazer - the man who penned Borat. And Bruno. And Ali G Indahouse - as this would have only served to dampen expectations to subterranean levels.
But I needn't have worried. I Give It A Year is a funny film.
It's not brilliant. It won't change your life. But there's enough here to make you chuckle away. The premise is simple. Two people (Rose Byrne's Nat and Rafe Spall's Josh) get hitched after a whirlwind romance, and promptly discover how ill-suited they are together.
Through plot contrivances that stretch credibility to breaking point (do people REALLY seek marriage guidance months after saying 'I do'?), they seek help from the excellent film-stealing Olivia Colman. These bits are great.
They also seek advice from friends, and in Josh's case the girl he was with before Nat. What you get are a series of sketches, each with their own plot line and joke. Some go on a bit long, sure, but overall there are chuckles aplenty.
Which is why it was somewhat baffling to walk away from the screening feeling I'd had an empty experience.
To paraphrase, all the bits are there - just not in the right order.
Part of the problem is in the editing. I suspect that the set-up of the film is supposed to be the couple looking back over their time together from the perspective of their therapy sessions. But this isn't made fully clear at the right time.
Instead, what you end up with is a couple of bits with Ms Colman around other bits that show how the pair are ill-suited. It all just feels a bit off-kilter.
The cast are great. Everyone is on top form - even if Rafe doesn't seem fully at ease playing the romantic lead. Stephen Merchant as the best mate, Minnie Driver as Nat's sister, Anna Faris as the ex, Simon Baker as the rich client - they're all on top form. Tim Key beats them all as the solicitor, mind, but hey-ho.
The writing is also a slight problem. It is clear that Mr Mazer has watched a LOT of romantic comedies. And the good ones, too. He knows which bits are needed, and as painting-by-numbers go he's ended up with a cute puppy.
Unfortunately he's painted outside the lines.
In an effort to 'push' the comedy, he's added more swearing and nudity than Richard Curtis would deem necessary, resulting in a kind of Four Weddings And An American Pie mash-up.
Where as in Pie you expected crudity and vulgarity by the bra-full, it jars when put up against the more sedate, gentile Four Weddings. You can have one or the other no problems, they just don't mix that well.
And there are moments when bits of dialogue just leap out at you, clearly having been lifted from real life (Mazer himself has said he's taken inspiration from his own life) - and it's frankly bizarre that these bits (I won't spoil them for you - have some fun and try spotting them) jar so drastically with the bits that have bubbled up from his imagination.
Normally, writers manage to blend the two seamlessly - but then, blending and mixing is clearly something Mr M has a problem with.
By the by, in a recent interview Mazer said he wanted to make an 'edgy' romantic comedy. It's as edgy as Hush Puppies.
Still, despite all that, this film does what it sets out to do. It's a comedy that makes you laugh. And in my case, laugh a lot.
Sure there are problems with it, but no one's perfect. You might not want a long-term relationship with I Give It A Year, but you'll have a fun night together.