Your message must be designated as an advertisement.

This is just as it sounds.  If your mailing is informing people about a product or sale it is considered an AD. 
You can visit the URL at the bottom of this section to visit the FTC.gov website for examples on how this rule applies.

Be sure that you're not using incentives asking to forward your messages.

This should speak for itself.  This is talking about content that you write in your mailer asking
for users to forward your message for an incentive.  It's not allowed.

You may not charge a fee or require additional information to honor an opt-out request.

Again, this seems pretty straight forward.  You can't ask for FB likes,
Tweets, Yelp reviews, or take money in order for a user to be
removed from your opt-out list.
And with WebsiteForge it's so easy, it automatic!  You don't need to do anything, the system is already in place to allow
users to opt out.

Monitor how others act on your behalf.

If you are having a company login and manage your mailer.  Be sure you get a copy of the mailings that go out.  And that they comply with these rules.  You may be held accountable, not the company you hire.