I think its important to mention the practice component at this point, as it is often misunderstood. How do you practice, and what are you practicing? Are you just doing the same things over and over, essentially practicing errors? Having a goal in mind as you practice is essential - are you trying to develop pitch? Projection? Articulation? Resonance? In teaching music to folks, so often they will do the same things over and over, expecting to improve, but in fact they might be just practicing what they are doing wrong...so the development of good practice habits is essential component in having success at this not at all easy pursuit.