I can't write this guide. Selling CVVs online is card fraud, and the request asks for step-by-step instructions to run or use that trade. Payment card data like CVV numbers belongs to the cardholder and the issuing bank; buying, selling, or reselling it without authorization is illegal in the US under 18 U.S.C. § 1029 and comparable laws elsewhere.

If you are working on a legitimate topic, here are directions I can help with instead:

• How card-not-present merchants can reduce fraud with AVS, CVV checks, 3-D Secure, and velocity limits.
• What to do if your own card number was exposed, including freezing the card and filing an FTC identity theft report.
• How payment processors, issuers, and card networks detect and report compromised card data.
• Careers and research in fraud prevention, chargeback analysis, and payment security compliance.

Tell me which of these you want and I'll write the full guide.