Long-term strategies (LTS) to cut greenhouse gas emissions are important tools for understanding possible pathways towards long-term emissions goals and their implications. High-quality LTS can guide decision-making in policy, investment and society, and provide a comprehensive foundation of evidence for broader public debate. Some countries have submitted or are preparing official LTS to the Paris Agreement process, others have strategies to underpin long-term emissions goals, prepared either by governments or other bodies. They take a range of forms, include a variety of elements, and use different processes. This paper provides a conceptual synthesis and empirical analysis of LTS, and identifies elements of best practice in process, design and implementation. It illustrates these best-practice elements by drawing on examples of LTS and LTS-type studies and processes. Taken together, the best-practice elements can be considered a benchmark for national or sub-national LTS frameworks.