Is it equipment? Skill? Originality? Imagination? Creativity? Productivity? Popularity?... Well, I guess this same question can be used in a more general sense.. Like "What makes a good artist?" BUT if you ask me, I think it all comes down to preference.
The other day I was talking to my friend, a graffiti writer and rapper, and we were discussing different styles in rapping. He said that people preferred mine over his, and he wanted to know why. I honestly told him that it wasn't because I was any better, really. It was probably because people liked MY way of delivering rhymes over his. Just like people might like his over mine, eventually. But I write this because people tend to get discouraged over why people don't like their music or artistic work. And I have some advice for you frustrated, discouraged individuals: Don't care! It's as simple as that. You do what you love, and if people like it or not... Well that's up to them. You're happy doing what you do, and at the end of the day, the one who matters most is yourself. Sounds a bit selfish, sure. But caring too much can harm your inner "creator", as I like to call it. Just remember to try your best in whatever you do, and strive for perfection in your craft, if it is what you seek. Not for others, but for yourself. So in closing, I say that a good musician is one who cares more about what he's doing than what people think about what he's doing.