Capture people when they are the most excited about your product. When a customer has made a purchase the anticipation leads to the moment to when they receive the package, take advantage of this accumulated excitement and try including a fun note that prompts them to share their purchase in social media and boost this by offering a promotion, a hashtag for a giveaway or any sort of reward and be sure to respond to those customers who do post something, this will keep customers happy, engaged and will attract new acquisitions.