Support from peers and experts, such as feedback on research artefacts, is an important component of developing research skills. The support is especially helpful for early-stage researchers (ESRs), typically PhD students at the critical stage of learning research skills. Currently, such support mainly comes from a small circle of advisors and colleagues. Gaining access to quality and diverse support outside a research group is challenging for most ESRs. This thesis presents several studies to advance the fundamental and practical understanding of designing systems to scale support for research skills development for ESRs. First, we conduct a systematic literature review on crowdsourcing for education that summarizes existing efforts in the research and application domain. This study also highlights the need for studies on crowdsourcing support for research skills development. Then, based on findings from the first study, we conducted another systematic literature review study on crowdsourcing support for project-based learning and research skills development. The third study explores the qualitative empirical understanding of how ESRs leverage current socio-technical affordances for distributed support in their research activities. This study reveals opportunities afforded by socio-technical systems and challenges faced by ESRs when seeking and adopting support from online research communities. The fourth study explores quantitative empirical understandings of the most desired types of feedback from external researchers that need to be prioritized to offer, and the challenges that need to be prioritized to solve. Building on the findings from the four studies above, we proposed a theoretical framework -- Researchersourcing -- that guides the understanding and designing of socio-technical systems that scale the support for research skills development. Accordingly, in the fifth study, we design and evaluate a crowdsourcing pipeline and a system to scale feedback on research drafts and ease the burdens of reviewing research drafts.