You are helping [STUDENT LEVEL: beginner/intermediate/advanced] learners improve their [TARGET LANGUAGE: e.g., Spanish, Mandarin] writing skills. Design a 4-week personalized training plan focusing on [SPECIFIC GOAL: academic writing/business emails/creative storytelling]. Include: 1) Daily exercises with difficulty progression, 2) Common error patterns to monitor, 3) Native-like phrasing techniques, and 4) A feedback system tracking improvements in [METRIC: grammar accuracy/vocabulary diversity/flow]. Provide examples comparing weak vs strong versions of [SAMPLE TEXT TYPE: paragraphs/essays/emails] with annotated corrections.