Tokenomics is the design and implementation of token economies in blockchain projects, which utilizes tokens as means of exchange, unit of account, and governance mechanism. Despite its significance, there is a lack of established frameworks for designing tokenomics from the start. Existing research often focuses on post-tokenomics or studying tokens as investment tools, leaving a gap in practical guidelines and best practices for creating sustainable token economies. This master thesis aims to address this gap by exploring the elements in designing self-sustainable tokenomics and proposing a potential framework. To accomplish this, an action research methodology was employed, collaborating with a leading blockchain company, and conducting interviews and workshops with the project participants. The results contribute to theory by establishing a three-phase and three-dimensional approach to design tokenomics and offer valuable insights for practitioners and researchers. By considering these findings and implementing best practices, blockchain projects can increase their chances of success and create sustainable token economies.