Training social workers to provide competent professional practice is of utmost importance. However, there have been ongoing dilemmas in enhancing practice competence in clinical social work, such as the challenges of selecting treatment approaches among numerous empirically supported approaches. Increasingly, common factors and common elements approaches are incorporated into clinical social work practice to address these issues, yet there is still a gap in addressing "how to foster skill building" in clinical social work. Using theories of psychotherapy integration and corrective experiences as a transformative change mechanism, we propose a microchange process, Activation-Contract-Processing (ACP), within sessions across various treatment approaches. This common process was developed based on both literatures and widely circulated master-tapes of therapy sessions from four empirically supported treatment models--cognitive therapy, behavioral activation, emotion-focused therapy, and interpersonal therapy. To guide social work students and clinicians, we elaborate on each step in ACP with illustrative examples around therapeutic proceedings, while incorporating core aspects of clinical social work, including but not limited to: person-in-environment perspectives, relationship, social justice and diversity, and evidence-based practice. We conclude by sharing the implications of the proposed common process to clinical social work practice, training, and research.