What is an effective way to advertise a certain product or service?
Without knowing what the exact product is, we can only give you a general to this question.
In general, the best way to advertise something is to make potential customers feel that they will in some way lose out if they do not have your product. This can be done in at least two ways. You can show the benefits of your product (such as when a car company shows its safety features preventing accidents) and leave it to your customer to infer what will happen (their family getting hurt in an accident) if they do not have your product. Otherwise, you can come right out and talk about the risks faced by those who do not have your product. Either way, the idea is to make the potential customer fear that they will in some way be harmed if they do not have your product.