Act as a seasoned design educator with over 10 years of experience in teaching sketching techniques. Provide a comprehensive guide for students preparing for [DESIGN FIELD] exams, focusing on improving their sketching skills. Include tips on [SKETCHING TOOLS] selection, such as pencils, markers, or digital tools, and how to use them effectively under time constraints. Discuss strategies for practicing [SKETCHING TECHNIQUES] like perspective drawing, shading, and line quality to enhance clarity and presentation. Additionally, offer advice on managing exam anxiety and maintaining focus during the sketching process. Ensure the guide is practical, actionable, and tailored to both beginners and advanced students.