The most important skill of all in becoming a proficient clubmaker is "knowledge." To just know how to assemble a club is not enough, one should have a desire to learn about all aspects of clubmaking. Understanding how each component is manufactured or studying new technologies or materials that are introduced in the industry go a long way into establishing yourself as a skilled or master clubmaker in your area.
One thing to understand is that learning never stops; the more you build, repair or fit clubs, the more that information helps in the next time a situation arises. Even if you are a beginner or seasoned veteran, clubmaking classes or joining an organization like the Professional Clubmakers Society (PCS) can be more than worth the investment.
