The 7 C's of effective communication are completeness, concreteness, consideration, clarity, courtesy, conciseness, and correctness. The document outlines each C, describing that communication should provide all necessary information (completeness), use specific rather than general words (concreteness), consider others' perspectives (consideration), avoid ambiguity (clarity), show respect through courtesy, be brief without repetition (conciseness), and have proper grammar and facts (correctness). Mastering these 7 C's can help convey messages effectively and build good relationships.