knowledge only because it is broad enough to encompass many skills under one heading.

Much like any other game you may hunt try and pick one thing that has made you successful...I mean truly just one skill? I'd say knowledge/experience would be the first thing most would say but deep down we know it is a combination of many skills that have equalled paydirt.

The 3 P's are very important as well:
Practice
Patience
Perseverance