The 7 C's of effective communication are clarity, completeness, coherence, conciseness, credibility, correctness, and continuity. Clarity means ensuring the message is easy to understand through logical organization and flow. Completeness means including all relevant details. Coherence ties ideas together under a main topic. Conciseness says everything needed in as few words as possible. Credibility builds trust through clarity. Correctness avoids errors that undermine trust. Continuity maintains focus on the subject without confusing jargon.