One way to increase sales is to give each new customer a one-time offer.
A discount is a typical option but it can be a bonus or free gift too. As long as it's something valuable.
You could make the offer conditional too, in that it'll only apply on purchases over a certain amount which you set based on your Average Order Value. e.g. If your Average Order Value is $34, make the offer apply on orders over $45.
This offer might help to convert customers who are on the fence or comparing you to a competitor.
Something to try out over the next couple of months.
If you haven't installed Repeat Customer Insights yet, it's an easy way to get a detailed look at your customer behavior, including the different Average Order Values for new and repeat customers.