Data donation, a research approach in which users voluntarily contribute their personal digital data, offers a solution to the limitations of traditional self-reporting and digital trace methods by enabling the collection of comprehensive, ethically sourced usage information across multiple devices and digital interfaces. However, this promising method remains underutilized due to low participation rates. Therefore, this review pursued two integrated aims. First, to synthesize evidence on factors that influence three forms of participation: hypothetical willingness (stated intention in imagined scenarios), actual willingness (consent to donate when asked), and successful completion (following through with the full donation process). Second, to appraise existing workflows, frameworks, and methodological tools and integrate this appraisal with the factor synthesis to derive best practices for improving participation. We synthesized 35 articles, of which 14 examined factors influencing participation and 21 provide methodological guidance. Five key factors were identified: sensitivity of the data, privacy concerns, perceived autonomy and control over the donation process, complexity of the process, and participant characteristics. To overcome barriers related to these factors, we recommend maximizing participant privacy through robust data donation frameworks, enhancing transparency and user-friendliness, empowering participants by increasing autonomy and control over their data, and proactively addressing potential selection biases.