Recommended eMail headers and content that help reduce bouncing

Question

It seems now, more than ever, the major service providers have cracked down on SPAM and really focused on filtering.

This is a huge concern for website's that require email validation, as users who do not receive instant emails are generally put-off the service all together.

So, my question is;

What are the most important keywords and headers required in an email to ensure the delivery to the major email service providers.

Also any other techniques; links to whitelist forms that allow you to submit your servers' IP(s)..etc will be a bonus.

Answer 1

1) Don't use a fake address, that's reeks of spam

2) Set up DomainKeys for your domain

3) Set up SPF for your domain