Well, a lot of people eat when they're really thirsty, or put liquid calories in themselves instead of water. If you have bad hydrating habits, upping your water intake will certainly help.
It isn't much of a secret, though. We all know by now that there's no such thing as a secret or key to weight loss. One rule: eat less than you burn. All the secrets and tricks we look for revolve around how to do this without going insane