Negative advertising can be effective when executed correctly and in adherence to certain guidelines.
It is crucial for the advertising campaign to be cautious, not violate any laws, and avoid using false or insufficient information about competitors.
Additionally, avoid personal attacks on competitors and creating a negative image of them.
Instead, focus on the quality of your product or service, compare it with what competitors offer, and highlight your advantages using the competitor's shortcomings as a backdrop.
Famous examples of negative advertising include Pepsi vs. Coca-Cola, Burger King vs. McDonald's, and many political campaigns: most of these are based on this principle.