The most effective measure for a counselor to know an individual before the counseling process is conducting an initial assessment or intake interview. This allows the counselor to gather relevant information about the individual's personal background, current issues, and goals for counseling. Additionally, using standardized psychological assessments, questionnaires, or surveys can provide further insight into the individual's psychological well-being, personality traits, and specific areas of concern. These measures help the counselor tailor their approach and intervention strategies to best meet the individual's needs.