The difference between a successful and failed marketing campaign is whether the target group is reached or not. As you already have a website and products, you know who your customers are. If your customers are mostly elderly people for example, it will be better to reach them by offline advertising such as direct mail. If your customers are young people, you will be more successful if you put time and effort to reach them online and on social media platforms. In the end it's all about playing your cards right, so you get as many sales as possible.
A marketing idea that I would recommend you is to give customers a discount on their first purchase. If you deliver in time and provide good service, you will get return customers.