how do you sell an idea?

There are a lot of ads today, especially with the increase of usage of electronics and the Internet. Ads can now reach a large amount of people in just seconds, and the reliance on a product makes avoiding such adds almost impossible. There are many ways to sell an idea, a lot of NGOs on environment tries to show a short documentary about the beauty of nature, and sell the idea of how wasting energy would destroy what we just viewed. Others would use threats, like what will happen when you do not change your method immediately. You can also sell an idea by saying that it is new, innovative and trendy, make people think that they are cool if they follow the idea. Whatever you do, do not sell the idea by using popup add, as it will just annoy the clients and cause negativity. Most people will rather buy something else than the products advertised on the popup add just to get revenge on their constant annoyance.