Understanding how to optimize product catalog feeds for Instagram commerce is the foundation of profitable shopping ad performance, yet many merchants deploy feeds with structural errors that suppress visibility and engagement. Catalog quality directly impacts ad delivery frequency, product impression share, and ultimately cost per conversion, because Instagram's algorithm prioritizes well-formatted, complete product data when selecting which items to show to relevant audiences. The guide details critical feed elements such as GTIN validation, image specifications, pricing accuracy synchronization, and category taxonomy alignment that distinguish high-performing feeds from underperforming ones struggling with low click-through rates. Practical sections address feed management workflows, how to automate updates from inventory systems, and methods for identifying and fixing attribute gaps that cause products to be suppressed from auction.