There's a lot of chaterati theories about brexit, so let me join in with mine...
I think the brits fell victim to their own over-inflated idea of media savvy. The advertising/media industry has long treated the UK as an experimental space for campaigns, think : Gordons gin adverts without any mention of the actual brand, or self-deprecating memes, or the traditional tight-knit social spaces like sports where you can find all the targets in one place (Guinness used this at cricket pitches, of old).
So how does this chime with my pet theory of why we fell, against almost all of our better interests, for the Brexit stories?
Well, the other side of the coin is that the majority of brits are pig-ignorant of the real world., despite going on hols in the costa brava - we have no idea who the president of France, or the minister for informatics of Greece is - by contrast, if you ask people in most of mainland Europe about such matters (i've tried) they know - they know details about our government and economics, and their own, and each others'. It is amazing, until you recall, they didn't politicise and under fund their state education systems.
So caught between these two clutch plates of clver marketing ("oh, yeah, can't fool me") and reality ("don't know about experts:), the population is easily fooled, even if it takes double bluffs.
So what to do next time? Well, let's take one concrete example - the leave campaign was good at memes - including epithets for their opponents ("remoaners") and the opposite cases being made ("Project Fear").
Of course, recently, a long piece in the Telegraph admitted that it now turns out most of Project Fear has come true. So what should the European Remain Group (to steal a Three Letter Acronym from its Arch Enemies) have done?
They should have embraced sophisticated marketing - Project Fear should have used images from Terminator and Mad Max and Blade Runner to show what was going to happen (Skynet would take over the markets in the UK, feral kids on motorbikes would scour the sewage drowned streets for gas, because it wasn't affordable, people would be huddled around fires burning books because they had no heat at home, and so on).
Next time, we will tell the truth, only better.