There are lots of sophisticated tricks and tips for marketing music, online and off. But if you mess up this one fundamental principle, you might as well not bother at all.

Music is pretty much unique when it comes to media consumption. You don’t buy a movie ticket because you liked the film so much, and while you might buy a book because you enjoyed reading it so much at the library, typically you’ll purchase first, then consume.

DVDs are, perhaps, a little closer to the music buying experience. You love a film, so you buy the disc. But generally, you love the film because you took a chance and paid to see it in the cinema.

But music is different — and radio proves that. By far the most reliable way to promote music is to have people hear it. Repeatedly, if possible — and for free. After a while, if you’re lucky, people get to know and love the music. Sooner or later, they’re going to want to own it.

This isn’t just true for pop music. It’s not just about getting a hook stuck in someone’s brain so they hum it to themselves as they take out the rubbish. So-called ‘serious’ music also benefits from familiarity — perhaps even more so. The more challenging a work, the more exposure is required to really get inside it and appreciate it.

Likewise, liking music is not just about entertainment. Music consumption, to many people, is a serious business. And by consumption, I don’t just mean buying or listening. It also involves collecting, organising and making sense of the music in relation to a personal canon. It takes more than an impulse purchase to break into that sphere.

But either way — whether it’s a pop tune, a heavily political punk album, or an experimental, avant-garde suite — the key is very simple: people have to hear music, then they will grow to like it, and then finally, if you’re lucky, they will engage in an economic relationship in order to consume (not just buy and listen to) that music.

That’s the order it has to happen in. It can’t happen in any other order. There’s no point in hoping that people will buy the music, then hear it, then like it. They just won’t.

This is not, I trust you’ll agree, rocket science. It’s perfectly obvious, straightforward and practical. And yet it’s the one mistake that most people make when promoting music online.

Nobody really wants to buy a piece of music they don’t know — let alone one they haven’t heard. Especially if it’s by someone who lies outside their usual frame of reference.

And a 30-second sample is a waste of your time and bandwidth. It’s worse than useless. That’s not enough to get to like your music. Let them hear it, keep it, live with it. And then bring them back as a fan.

More than ever before, you have to build that relationship, because it’s easier than ever before to just not bother and simply go elsewhere. Elsewhere, after all, is right here too. No matter how good your music, it’s competing with millions of other choices. Millions.

The simplest way to promote music and build an economic relationship with a consumer is to let them hear it. Let them hear it repeatedly, without restriction. Let them grow to love your music and hear it as a part of their collection. Then they will want you to have their money.

This is not just a truism about music online — it’s also just how capitalism works. You provide value, then you are rewarded with money.

You don’t get the money first — and you don’t get to decide what value is.