One of my best tips for people who are wanting to increase online sales is to use your Web site as a way to increase sales from existing customers. The people who have already bought from you in the past are more likely to buy from you in the future. Using an existing mailing list to let people know about your site and its offerings is an inexpensive method of boosting online sales for lots of companies. For those of you who are selling online with some success, how do you increase your online sales?