I think part of the campaigning problem was Brexiters had very carefully crafted emotional messages, either scapegoating immigrants - which we know plays well to certain crowds, or telling outright lies - like the EU killing the British fishing industry & all of that money that will flow into NHS. But these messages, even though they're emotional scapegoating or just blatantly lying... they work with people.
Much of what remainers were campaigning on was "we have a net benefit to being in the UK and voting on something we don't really know will cause instability which can lead to x, y, and z." A lot of people that wanted us to remain were wanting the UK to remain in the EU for economic stability.
Economic stability vs. compelling lies and emotional arguments is a tough battle to win. Especially when for a lot of people, there isn't a whole lot of "economic stability" - a lot of people have experienced either a rough start to their careers or have had some shit experiences with economic downturns in the last few decades. However that's a bit missing point of how Brexit would impact the biggest contributor to the UK's GDP... or failing to really understand how leaving the EU can impact British trade - and the ripple effects in our economy of fucking with these things.
It's not a winning argument for most people, in all honesty. You can say "well it's really very complicated and we don't know how it will work out, but it will have major impacts to major parts of the British economy and we shouldn't be voting on a Brexit without a clear and concrete plan for Brexit because of x, y and z" when the counterpoint is a mix of "LOOK HOW MUCH MONEY THE NHS WILL HAVE," "THIS WILL RESTORE FAILING INDUSTRIES," and "FUCK OFF YOU FUCKING POLES AND FILTHY MUSLIMS." And the fact the referendum was to trigger Article 50 with no real fucking plan for Brexit just shows how fucking stupid our political leadership and voters are. At a minimum, the referendum should have been "are we going to plan for Brexit or not" rather than just trigger Article 50 and think we can just fucking bumble our way through negotiations with the EU when they've got all of the fucking leverage.