3 ideas
A goal is a specific outcome you either hit or miss, leaving you in failure mode until the moment you achieve it; a system is a recurring process you do regularly to increase your odds of success over time, like writing daily rather than aiming to publish one book. Systems people convert each repetition into improved skill and expanded opportunity, so they win even when any single attempt fails.
Rather than becoming the best in the world at one skill, combine several ordinary skills that are each in the top 25% so their intersection makes you rare and valuable. Adams attributes his cartooning success not to elite drawing or writing alone, but to the rare combination of average drawing, decent humor, and business knowledge.
The single criterion for prioritizing decisions about diet, exercise, work, and relationships should be whether they raise or lower your personal energy, because high energy makes you more productive, optimistic, and attractive to opportunities. Choosing activities that energize you over those that drain you compounds into broad life advantage that no single skill provides.