Marty Cagan’s article on the characteristics of a good One on One meeting is great advice for managers, but it also includes some excellent points about what makes a good product manager in general. Here, for example, is a section on what it means to think like a PM:

What does it mean to think like a PM? It means focusing on outcome. Considering all of the risks – value, usability, feasibility and business viability. Thinking holistically about all dimensions of the business and the product. Anticipating ethical considerations or impacts. Creative problem solving. Persistence in the face of obstacles. Leveraging engineering and the art of the possible. Leveraging design and the power of user experience. Leveraging data to learn and to make a compelling argument.