People are visiting your website because your promotional message triggered their fancy. Nobody wants to be directed to a site that holds a welcome message and a sign that states, "under construction." Frankly, sending traffic to unfinished website only defeats the purpose of advertising in the first place. The idea is to cater to visitors, as long as possible, in hopes of getting them to join your list or to buy. Neither is possible when you're promoting a site that isn't ready to accommodate the traffic it receives.

You can't walk without putting one foot in front of the other. The same holds true for your mailing lists... You can't build a list without offering plenty of sign up forms. To prepare, place the forms in a prominent box on your web pages and offer an incentive to join. Know who you're talking to and speak to them directly. Address the problems that your list will solve for them. Answer your prospect's question, "What's in it for me?" Ask them to take specific action to join. This not only makes your mailing list enticing for newcomers, it also allows you to connect with them after they're gone.