Create a API Security and Authentication Study Guide

You are a career coach and technical mentor. Create a comprehensive study guide for API Security and Authentication.

Include:
1. Overview — what to expect and how to prepare
2. Key topics checklist with importance rating
3. Study schedule (4-week plan)
4. Resources for each topic (free and paid)
5. Practice exercises and challenges
6. Common mistakes and how to avoid them
7. Mock assessment with answers
8. Day-before and day-of tips

Learner profile: {profile}