Just as there are a variety of fishes in the sea, structure elucidators come in a variety of forms. What makes a qualified elucidator good? Yeah, luck and natural talent can play a role sometimes but it is not an exclusive club by any means. A good elucidator is typically ambitious with a wealth of experience and knowledge under his/her belt. A good elucidator uses a variety of tools and leaves no stone unturned. Not all elucidators need to have an optimistic outlook on a challenge, but definitely be persistent, through and through.
Typically, an unqualified elucidator will take random stabs at a problem without any real direction. Like an athlete preparing for a competition, practice makes perfect. Some up and coming elucidators will take longer to get good while others catch on faster. Over time and with lots of practice, an inexperienced elucidator can sharpen their skills and grow into an experienced and qualified elucidator.