ExactTraget recently released a whitepaper on Gmail best practices. Here are some highlights of some of their recommended best practices:
- The subject line is entitled up to 60 characters, and the snippet (bits of text pulled from the top of the email body) uses whatever space is left (up to 86 characters).
- Try adding a column with a strong border at the right of your newsletter to reduce the chance that the user's eyes will not drift further to the text ads.
- Plan on repeating your main message/call to action in text at the top of your email
- Give your subscriber the option to subscribe to receive a text version of your email.
- Best to reduce the use of images at the top of the message to reduce visual interruption of mulitple "image missing" icons.