When I think back on my 3,000+ career counseling clients and my successful and not successful friends and colleagues, it's clear to me that the #1 factor in success is focused drive: the willingness to work hard and be focused, not dabble around.
Whether in trying to land a job or succeed in one, unlike in Hollywood portrayals, the hard worker usually prevails. Of course, sometimes despite hard work, one fails, but focused drive usually is necessary.
For example, when I give talks to unemployed people and ask them to raise their hand if they're a procrastinator, 80 to 90% do. When I ask the same question of a group of successful people, for example, executives or college presidents, only 10-20% do.