The article substantiates the possibilities of developing promising skills of the XXI century, in particular soft skills, as a set of non-specialized, super-professional skills, which, unlike specialized, are not related to a specific field of professional activity. The leading means of developing such skills are STEM-projects, which combine the basic elements of research, project activities and take into account the external requirements of a particular activity. The analysis detected that common skills that were relevant 5 years ago and were envisaged for today, were such as interaction with people, integrated problem solving, creativity, critical thinking, the ability to form own opinions and make decisions, the ability to listen and ask, flexibility of mind (the ability to quickly switch from one thought to another) and emotional intelligence. In most scientific papers, the key soft skills include creative thinking, information management, emotional intelligence, the ability to form own opinions and make decisions, presentation skills. Based on this, the emphasis is on changes in the formation of soft skills and their development. At the theoretical level, methods of developing key skills include trainings, seminars, mastering models of successful behavior, finding feedback, learning from the experience of others, identifying models of successful behavior of people with a high degree of development of certain competencies. The development of soft skills requires special methods that focus on critical thinking; creativity; organizational skills; team working; emotional intelligence; problem assessment and decision making; ability to interact effectively; cognitive flexibility; versatile development of individuality; formation of a holistic scientific worldview of students; formation of a holistic scientific worldview of students; formation of a personality capable of independently choosing and making responsible decisions; education of students' respect for work, providing conditions for life and professional self-realization, formation of readiness of a conscious choice and mastering of the future profession. It is proved that the driver of the development of key competencies and skills of the future in students is STEM education in general and STEM projects in particular. The scheme proposed to the participants of the All-Ukrainian online-contest “Teacher of the Year” on the version of science journal “Kolosok”, who competed in the category “STEM teacher”, is highlighted.