...you need to spend as much time talking to prospective customers as you do working on your product...
Better yet, use your customers' day-to-day problems as seeds for your idea. Better to scratch their itch than your own if you can. This would be a huge head start.
Even if you're directly targeting a known issue, it's very possible they won't want to pay for the solution. A tight feedback loop is necessary in damn near every product's development, I believe.
Just today there was this call from the guy behind 'wordoid', textbook case of tight coupling with the customer base. Very interesting to watch, that was his second iteration and he does a fantastic job of it.
Better yet, use your customers' day-to-day problems as seeds for your idea. Better to scratch their itch than your own if you can. This would be a huge head start.