Of late I have started to question whether your talent alone is sufficient to get you to the success that you desire.

But more often than not, I have realized that it is not the case, you need discipline, consistency and persistence to be successful.
It is very disheartening to be an unsuccessful man with talent.
And hence the only thing or habit that you can trust is persistence. Nothing can take the place of committed, consistent efforts that you make towards your goal.
Sure in the beginning things look like a struggle and it's difficult to keep at something when you don't see the results, but that is the catch. I have opted to drop out, move away or just leave many a things in life when I saw that I am not getting any immediate returns and it took me many years and a lot of failures to realize the importance of persistence and that you cannot just leave things in between when the going gets tough.