Artificial Intelligence (AI) ethics has become a prominent topic due to public concern about the rapid integration of AI into daily life. Although prior research has focused on aspects of AI ethics, the views and experiences of AI practitioners have received little attention. This thesis reports on AI practitioners' perspectives and experiences on ethics of AI-based systems, specifically fairness. A framework, recommendations, and a software-based tool were developed to guide ethical AI development, ensure fairness, and raise awareness of AI ethics among practitioners. It lays a solid foundation for further research and practical advancements in the field of AI ethics.