You can use multiple ways to study your customer base and prospects. You can do it by using metrics, by visiting the kind of websites they visit, or mailing list by the kind of products and services that they buy but you have to do it. This will be helpful because if you know your customers you don't have to offer them everything you sell. You only have to target them and give them what you know they want.
Email each of your customer segments with what they're looking for and they'll stick with you. Work on follow-up emails: You need to have a follow up email ready to be sent once somebody signs up for your mailing list. It is as simple as mailing list sending out an email welcoming a new subscriber and taking them to a start page with instructions and information about what he or she can do now that they're signed in!
Run periodic maintenance checks on your Mailing List: You need to run a periodic maintenance check on your mailing list to know where your resources are going. It is just not worth it to have users getting your emails in their spam folders, or mailing list have dead addresses on your list. Make sure you do this clean up from time to time. If you don't have a mailing list right now then chances are that you're relying solely on your website or blog itself to communicate with your visitors and to try and drive sales.