How to cancel a flight booking without losing all my money?

Here is what helped me:

1. Check the 24-hour rule. For flights to or from the US, if you booked at least 7 days before departure, you can generally cancel within 24 hours for a full refund.
2. Look at your fare type. Refundable fares return money, while non-refundable ones may give a credit.
3. Ask for taxes and fees. These are often refundable even on non-refundable tickets.
4. Cancel before departure. A no-show can cancel your return flight too.

This how to cancel a flight booking guide explains the steps well.