Keeping things simple; when setting up your sign-up form for your website keep three things in mind:
1. What information to ask from those signing up for your email newsletter
2. Setting up a custom 'Thank You' page. This is where the subscriber will be re-directed after successfully signing up for your newsletter.
3. Setting up a custom 'Error' page. This is where the subscriber will be re-directed if there is a problem during the sign up process, such as entering an invalid email address.
Ask for Minimal Information
When possible it is always better to ask your visitors for minimal information. I typically ask for first name and email address. This is important because your website visitors will most often read quickly and will not bother completing a long form when signing up for your newsletter. Remember, you can always ask for additional information later if needed.
Thank You Page
After signing up for your newsletter, be sure to re-direct your visitors to a custom 'Thank You' page. Email marketing software, such as IntelliContact, include a default 'Thank You' page but allow you to simply insert a URL to redirect subscribers to a custom page hosted on your server. This page should contain a simple message such as:
"Thank You for signing up for the XYZ Newsletter. Our newsletter is a monthly publication that will help your business by bringing you up-to-date information on the technology industry."
Implementing a custom 'Thank You' page will also allow you to provide consistent navigation after a subscriber has successfully signed up for your newsletter (IE: the 'Thank You' page looks like the other pages of your website). This will encourage the subscriber to extend their stay on your website.
Another great opportunity in having a custom 'Thank You' page is co-registration. Co-registration is a great way to build your lists. Basically, within your 'Thank You' page you can include links to partner websites where visitors can sign up for other newsletters that compliment yours. In exchange, these 'partner websites' include a link to your website from their 'Thank You' page where subscribers can sign up for your newsletter.
Error Page
When creating your sign-up form and 'Thank You' page, also include an 'Error Page' where subscribers will be re-directed in the event that they neglect required information or fail to enter a valid email address. Most email marketing software programs allow you to enter a custom 'Error Page' as well. It is also a great idea to include your sign-up form again on your 'Error Page'. This will allow the subscriber to simply fill out the form within the same page and save them from clicking the back button. For your custom 'Error Page' include text similar to the following:
ERROR
There was an error in completing your subscription request. We apologize for the inconvenience. Please use the form below to sign up for our newsletter. If you continue to receive an error please email us at name@yourcompany.com.
Remember to include these two pages when designing and implementing your sign-up form. By keeping it simple, straight-forward, and thinking about the subscriber's experience through the process, you'll see an increase in the number of subscribers signing up for your email newsletter.

About The Author

Brandon Milford is the Executive Director of Marketing for Broadwick Corporation, makers of IntelliContact (www.intellicontact.com). IntelliContact is an industry leading email marketing and surveying application. Brandon is considered a thought leader in web marketing and through Brandon's Blog (www.brandonmilford.com), he shares his insight on marketing, design, and entrepreneurship.
brandon@broadwick.com