The most effective way to secure a discount on Booking.com is through the Genius Loyalty Program. Simply by signing in, you can access "Genius" rates that are at least 10% off. As you book more stays, you move to Level 2 or 3, which can offer 15% to 20% discounts and free breakfasts. Another major strategy is using the Booking.com mobile app, as many properties offer a specific "Mobile-Only Price" (usually an extra 10% off) that isn't visible on a desktop browser. You should also look for "Getaway Deals" during seasonal transitions. Lastly, checking the "Secret Deals" section—available only to registered members—can provide deep cuts on luxury properties. Always ensure you are logged in, as the algorithm prioritizes showing lower, member-only rates to returning users who have a history of completing stays.