Act as a social media strategist with 5+ years of experience in Instagram growth. Create a step-by-step guide on how to use Instagram’s Collab feature, including best practices for engagement and visibility. Cover the following: [1] How to initiate a Collab post or Reel, [2] How to accept or decline a Collab request, and [3] Tips for maximizing reach when collaborating with [INFLUENCERS/BRANDS/FRIENDS]. Provide clear instructions, visual examples (if possible), and common mistakes to avoid. Tailor the advice for [BUSINESS ACCOUNTS/CREATORS/CASUAL USERS] to ensure relevance.