In this guide, you’ll learn how to select a product to sell that’ll make you money and how to write the most persuasive marketing copy possible. More generally, you’ll learn how to take advantage of clear-headed moments to do your best work and recover when you’re feeling mentally drained. In our commentary, we’ll supplement the authors’ advice with perspectives from marketing as well as general self-help. We’ll also update information that’s out of date or incomplete with new knowledge about marketing practices in the digital age.