Emails landing in Gmail Promotions tab

I want to first mention that an email landing in the Promotions tab is still considered a successful inbox placement by Gmail. That being said, Gmail does not make their inbox tab sorting algorithms public. While there are many articles online that purport to have tricks and strategies for sidestepping the inbox tabs system, there is no reliably proven way for a sender to force an email from Updates/Promotions/Social etc into the Primary inbox tab.

The only methods we've found that can sort emails to the primary tab is to encourage your recipients to:

• Drag your emails from Promotions to Primary. This is the only known method of 'training' googles sorting algorithm in a legitimate way.
• Prompt your users to add your From address to their address book in Gmail.

One thing to keep in mind is that emails being sorted into tabs can end up being a good thing overall. Gmail tabs have actually been proven to reduce instances of recipients marking messages as spam in studies conducted by ReturnPath.