Make it more convenient. And people will pay for it. Duh!
Arnold King nails it:
It really is simple. If you have the most convenient distribution system, then you do not have to worry about somebody "stealing" your songs, or you movies, or what have you. People will pay for convenience. On the other hand, the more you try to "protect" your content, the less convenient you make it, and the less revenue you are likely to earn from it.