While the essence of brewing lies in experience and attention to detail (especially hygiene) the one absolute essential is a good palate. Being able to taste, criticise and evaluate your beers and others is where brewing succeeds or fails. Ingredients are a level playing field apart from some exotic hops - all breweries have access to the same set of ingredients. And as many breweries have proved, you don't need fancy kit to brew great beer. Good beer comes from understanding how best to use those ingredients, creative imagination, and attention to the vast minutiae of brewery operation. Oh, and don't ever be boring.