The relationship you have with your email subscribers is just like dating: You meet, get together a few times, and before you know it, you're going together. You'd like nothing better than to make it permanent, but the decision isn't entirely up to you. How can you tell if your email marketing relationship is altar-bound or heading for the big break-up?

Having a knockout email subject line is your first and best opportunity for attracting attention in an overflowing inbox, but it is only the start. Your readers have to trust that your message is worth the cost of a few seconds of their day, even if they don't buy the product you're offering.