For more information: https://www.wizxpert.com/how-to-follow-up-with-new-customers/ 

The best way to increase product sales is to follow up with new customers; it is necessary to build trust among them. Whenever you purchase goods from an online store and do not receive your product delivery on time, it causes a headache for the customer. Therefore, customers always seek customer service, which is the hope of every customer for their query. Customer service is the only way to build trust among new customers as well.

You should always focus on the correct channel, not from a single channel. Contact new customers by using email, phone calls, or even social media, and provide such advertisements that are related to the customers' needs to get their instant interest.  

You can build trust by providing users with the best customer service so that they believe in you. Stress them out by giving answers to their queries, always thank them for their understanding, provide coupon codes and vouchers so that they build interest in your product, always ask for feedback, and ask how users think of your product and service. Give the customer special gratitude, dont just give a one-time product sale, you should often provide helpful and high-value content to manage the engagement of the customer.