Generate a full detail guide on dropshipping for beginners. The guide must be realistic and comprehensive. It should include detailed sections on: 1. How to find a profitable and low-competition niche. 2. A detailed checklist for vetting dropshipping suppliers (e.g., on AliExpress or other platforms). 3. The technical setup: Connecting your e-commerce store to a dropshipping app. 4. How to market a product you never physically touch. 5. A guide to managing customer service, shipping expectations, and returns. Please include a disclaimer about the challenges of this business model.