If you were to market a product, what would you do?

Get some beta testers who are online a lot to spread word of mouth. Perhaps see if any pro reviewers will review it. And find the kind of dealer that trusts their own ears rather than marketing to see if they will champion it. That's what comes to my mind and yes audio clubs are also a good idea.

Europeans often are more open to new things, Americans tend to be more conservative. I would try to involve them too.
What product are you talking about? Cables and speakers might require different approaches.

Beta testers as @jond suggests, is certainly one avenue, though this is more common with items that are easier to ship, and less susceptible to damage from shipping, like cables.
For larger items, perhaps asking if you could host at some audio clubs could also provide some feedback, or stimulate sales.

Peter, you might try giving Bob Backert of Backert Labs a call, as I'm sure that he would have more developed ideas. He has launched his own brand after many years of providing repairs and upgrade service for many big brand name electronic gear.

Good luck,
John