A skill set good enough to win once has an expiry date, because the field moves and the standard moves with it. The trap after a success is treating your current method as proven and therefore finished, which holds up for a few years and then quietly stops. Winning is the worst moment to stop learning and by far the most tempting one. Everybody around you is still improving.

Straight after something goes well, pick one thing to get better at that had nothing to do with the win. Be willing to be bad at it for a while.