Psychosocial guidelines and standards systematically describe stressors and resources in particularly challenging situations and hence serve as a basis for interventions to achieve defined psychosocial goals. Despite fundamental principles and guidelines for psychosocial methods, the quality of provided care varies considerably depending on setting, provision, and profession. The purpose of the present protocol is to illustrate the development and evaluation of the standardized psychological intervention "My Logbook", a practical guide accompanying children through all stages of treatment by directly translating current quality standards of psychosocial care into practice. In an evidence-based set-up, using face-to-face discussions and telephone conferences, a multi-professional team of local experts decide on critical disease-related issues, structure, content (information and intervention elements) and design of the quality improvement tool. Via delphi surveys an extended expert team is asked to rate the content, method, and design of all booklets which is concluded by a final agreement by the specialist group for quality assurance of the psychosocial working group in the Society for Pediatric Oncology (PSAPOH). The developed tools are piloted in an international multicenter study to evaluate the patient-reported outcome and feasibility and to integrate practical views of patients, as well as psychosocial and interdisciplinary professionals into the further development of the "My Logbook". The iterative development of the "My Logbook" including local and international experts as well as the patient and practical perspective allow for the design of a process-oriented, consensus - and evidence-based tool directly translating the S3-Guideline into clinical practice. Feasibility and applicability are fostered through an iterative process of constant evaluation and adaptation of the tool by international experts and through the clinical experience gathered in the multi-centered pilot study. Furthermore, the systematic evaluation of the tool by patients, psychosocial, and interdisciplinary professionals enables the identification of persisting gaps between evidence-based standards and clinical practice, discrepancies between the various stakeholders' perspectives as well as regional differences in feasibility, thereby directly linking practice and research. The preliminary results emphasize that psychological support can be standardized, enabling an evaluation and optimization of psychosocial care which future studies need to assess in multicenter clinical randomized controlled trials.