Let your ads follow those visitors who previously visited your website
Ads that follow users!
Make sure your message is continually being shown to people who have visited your website, if they have shown and interest in visiting your site then they are much more likely to buy from you, when the time is right, make sure your message is infront of them when that happens.
Make sure they are relevant!
Great your message/ad is following visitors to your site but you have to make sure it is relevant and you are not trying to sell carpet cleaning to those interested in wooden floors…