I don't know who this guy is. I don't know his painting. He's long winded. He's basically trying to sell his DVD training set. But, he makes some excellent points. He's got three tips to "cure amateurish looking painting."
1. Preserve integrity of brushwork. Don't make little feather-like strokes with your brush. Paint the damn line.
2. Be authoritative. Even if the line is wrong. Make it strong. Strong brush strokes.
3. Use more paint. Don't make a stained canvas. Make a painting.