1. You're easy to get to know, but you don't come on too strong.
You give browsers the opportunity to subscribe everywhere they come in contact with you: a link to your email registration page on every page of your website; an invitation in any emailed correspondence; offline registrations at trade shows, point of purchase or even personal contact. At the same time, you never try to force the relationship by using a pre-checked box on the registration page, buying a list, or emailing to anyone who didn't ask to meet you. (Read: Permission) And, you don't force them to fill out a detailed demographic profile before getting to the opt-in. That's like asking too many personal questions before they agree to the first date.
2. What they see is what they'll get.
You describe your email program in depth at your site, offering to show a sample mailing and giving them the opportunity to tell you what they want with options for content, format and frequency. You also tell potential dates exactly how you will use the information they give you and link to a privacy policy written in plain language, not legalese.
You acknowledge all subscription requests immediately by confirming opt-ins and then sending out a welcome message that recaps what they signed up for, introduces them to your program, and invites them to deepen the relationship by telling you more about themselves on a detailed profile update page. You even sweeten the deal with a special email-only offer, like a discount coupon, a collection of "best-of" articles or other thoughtful touches that make you stand out in the crowd(ed inbox). You also nurture the email relationship and show them that you're paying attention by contacting them if you see they haven't been opening your messages and asking what's wrong.
4. You respect them and their preferences.
If they said they want to see you only once a week, you don't call them every day to see if they want to go out. (Read: Frequency) If they want to receive only site updates, you don't send sale flyers. You never pass their names on to your buddies if they want to be alone with just you.
5. You pay attention to them all the way through the relationship.
You notice when they begin to withdraw from you, when they stop opening or responding to your email messages. Instead of drifting apart, you create targeted mailings just for them, with special offers or invitations so they know you are thinking of them and want to win back their love.
6. If they want to break up, you exit gracefully and try to stay friends.
No matter how hard you try, not every subscriber relationship lasts forever. Often, it's not you, it's them. Their needs or lives change, and you don't have a place anymore. Instead of trying to cling to them and hope they stay, you make it easy for them to walk away by honoring their unsubscribes immediately and not begging them to come back in follow-up emails. It might just be a temporary thing after all; if you part on good terms, they'll find it easier to come back to you.