Know your customer. Keep a database with information about your client such as: what they purchase, how often they purchase and the last time they purchased. If you have an online store this shouldn’t be too difficult to establish and maintain. These are important because if you know what they purchase you can send them information on similar or complementary items. Knowing how often they purchase will allow you to be more proactive in the timing that you send them information on similar products. Finally, knowing the last time they purchased will help you determine if you’ve lost them as a customer. If they usually purchase every month but you haven’t heard from them in two, that’s a red flag that maybe you’re not meeting their needs anymore.