After the release of several widely adopted artificial intelligence (AI) literacy guidelines by 2021, the unprecedented rise of generative AI since 2023 has transformed the way we work and acquire information worldwide. Unlike traditional AI algorithms, generative AI exhibits distinct and more nuanced characteristics. However, a lack of robust understanding of generative AI hinders individuals' ability to use generative AI effectively, critically, and responsibly, which we can call generative AI literacy. To address this gap, we reviewed and synthesized existing literature and proposed generative AI literacy guidelines with 12 items organized into four aspects: (1) generative AI tool selection and prompting, (2) understanding interaction with generative AI, (3) understanding generative AI outputs, and (4) high-level understanding of generative AI technologies. These guidelines aim to support schools, companies, and organizations in developing frameworks that support their members to use generative AI in an efficient, ethical, and informed way.